feat: full CoinMarketCap-style crypto portfolio (buy/sell log, 1h/24h/7d%, P&L)

Replaces the plain quantity field with a CryptoTransaction log (same "record events, derive the total" shape as Goal/GoalContribution): quantity and average buy price are now computed via weighted-average cost — a buy blends into the running average, a sell reduces quantity but leaves the average cost of what's still held unchanged. Switches price fetching from /simple/price to CoinGecko's /coins/markets (still one batched call for every coin), which also returns 1h/24h/7d % change in the same request. Old PATCH /crypto/holdings/{id} is replaced by POST .../transactions (buy/sell, rejects selling more than held), GET .../transactions (history), and DELETE /crypto/transactions/{id}. Frontend: CryptoHoldingsTable replaces the simple list with a real table (Name/Price/1h%/24h%/7d%/Holdings/Avg Buy Price/Profit-Loss/Actions), horizontally scrollable on mobile rather than dropping columns. New CryptoTransactionModal (buy/sell) and CryptoTransactionHistoryModal. Backend: 79/79 tests passing (13 in test_crypto.py, up from 9). Also verified live end-to-end against the real CoinGecko API with the user's own key — create, buy, sell, oversell rejection, history, manual refresh, all against real BTC/ETH prices in EUR — test data cleaned up after. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01855PiW5Wd8n4aRW4n9kByY
2026-10-13 02:56:39 +07:00 · 2026-08-30 04:25:03 +03:00
parent 7e4508d1de
commit e8cd536584
24 changed files with 1154 additions and 374 deletions
--- a/DOCS.md
+++ b/DOCS.md
@@ -505,14 +505,21 @@ personal vehicle)

 ## Crypto

-Live-priced crypto holdings — a coin plus a quantity, kept current against
-[CoinGecko](https://www.coingecko.com/en/api/pricing)'s Demo API. Under the hood each holding **is** an
-Asset (`asset_class=crypto`, see [Assets & Net Worth](#assets--net-worth)) — deleting one is `DELETE
-/assets/{asset_id}`, not a separate endpoint, and it shows up in `/net-worth/summary` like any other
-asset automatically.
+Live-priced crypto holdings with a full buy/sell history — a CoinMarketCap-style portfolio view, kept
+current against [CoinGecko](https://www.coingecko.com/en/api/pricing)'s Demo API. Under the hood each
+holding **is** an Asset (`asset_class=crypto`, see [Assets & Net Worth](#assets--net-worth)) — deleting
+one is `DELETE /assets/{asset_id}`, not a separate endpoint, and it shows up in `/net-worth/summary`
+like any other asset automatically.
+
+**Quantity and average buy price are never sent directly — they're derived** from a log of buy/sell
+transactions, using the weighted-average-cost method: a buy blends into the running average cost; a
+sell reduces quantity but leaves the average cost of what's still held unchanged. This is the same
+"record events, derive the total" shape as [Goals](#goals)' contribution log.

 Requires `AURUM_COINGECKO_API_KEY` in `.env` (a free Demo key, no card required). Endpoints that need
-CoinGecko return `400` with a message telling you so if it's unset.
+CoinGecko (`/crypto/holdings` on creation, `/crypto/refresh`, `/crypto/search`) return `400` with a
+message telling you so if it's unset — adding a transaction to an existing holding never needs it at
+all (see below).

 Prices are **never** fetched in the background — there's no scheduler in this stack. Two triggers
 only: `POST /crypto/refresh` (a manual "refresh now"), and a lazy check on every `GET
@@ -522,13 +529,15 @@ of the whole request failing.

 | Method | Path | Description |
 |---|---|---|
-| `GET` | `/crypto/holdings` | List holdings with their live value. Also runs the lazy once-a-day auto-refresh. |
+| `GET` | `/crypto/holdings` | List holdings with live price, 1h/24h/7d % change, computed quantity/avg buy price/P&L. Also runs the lazy once-a-day auto-refresh. |
 | `POST` | `/crypto/refresh` | Force a price refresh right now, bypassing the 24h window. |
-| `POST` | `/crypto/holdings` | Add a holding — fetches today's price immediately so it isn't `null` until the next sync. |
-| `PATCH` | `/crypto/holdings/{asset_id}` | Change `quantity`. Recomputes value from the last known price — does **not** call CoinGecko. |
+| `POST` | `/crypto/holdings` | Add a new holding — its first buy transaction, inline. Fetches today's price immediately so it isn't `null` until the next sync. |
+| `POST` | `/crypto/holdings/{asset_id}/transactions` | Buy more of, or sell some of, a coin already tracked. Never calls CoinGecko — value is recomputed from the last cached price. `400` if a sell would exceed what's currently held. |
+| `GET` | `/crypto/holdings/{asset_id}/transactions` | Full buy/sell history for one holding, newest first. |
+| `DELETE` | `/crypto/transactions/{transaction_id}` | Remove one transaction; quantity/avg buy price/value are recomputed from what's left. |
 | `GET` | `/crypto/search` | `?q=` — search CoinGecko for a coin to add (name/ticker, returns its `coingecko_id` + logo). |

-**Create body:**
+**Create body** (`POST /crypto/holdings`):

 ```json
 {
@@ -536,13 +545,25 @@ of the whole request failing.
  "symbol": "btc",
  "name": "Bitcoin",
  "thumb_url": "https://...",
-  "quantity": "0.05"
+  "quantity": "0.05",
+  "price_per_unit": "55000",
+  "date": "2026-08-01",
+  "note": null
 }
 ```

 `coingecko_id` is CoinGecko's own stable id (not the ticker — tickers collide across unrelated
-coins) — get it from `/crypto/search` rather than guessing. `quantity` supports up to 18 decimal
-places (wei-level token amounts).
+coins) — get it from `/crypto/search` rather than guessing. `quantity`/`price_per_unit` support up to
+18 decimal places (wei-level token amounts). `price_per_unit` is what you actually paid, in the app's
+display currency — it's stored as-is, never re-derived from market data later.
+
+**Add a transaction** (`POST /crypto/holdings/{asset_id}/transactions`):
+
+```json
+{ "type": "sell", "quantity": "0.02", "price_per_unit": "61000", "date": "2026-08-30", "note": null }
+```
+
+`type` is `"buy"` or `"sell"`.

 **`GET /crypto/holdings` / `POST /crypto/refresh` response:**

@@ -559,17 +580,25 @@ places (wei-level token amounts).
      "name": "Bitcoin",
      "thumb_url": "https://...",
      "quantity": "0.05",
-      "value": "3000.00",
-      "unit_price": "60000.00",
-      "as_of_date": "2026-08-30"
+      "avg_buy_price": "55000.00",
+      "current_price": "61000.00",
+      "price_change_1h": "0.12",
+      "price_change_24h": "2.30",
+      "price_change_7d": "-1.80",
+      "value": "3050.00",
+      "cost_basis": "2750.00",
+      "profit_loss": "300.00",
+      "profit_loss_percent": 10.91
    }
  ]
 }
 ```

-`value`/`unit_price` are `null` only for a holding whose very first price fetch failed (CoinGecko was
-down right when it was added) — distinct from a real `0`. `error_key` is `"unreachable"` when this
-sync attempt couldn't reach CoinGecko (existing values are kept as-is), or `null` otherwise.
+`current_price`/`value` are `null` only for a holding whose very first price fetch failed (CoinGecko
+was down right when it was added) — distinct from a real `0`. `avg_buy_price`/`cost_basis`/
+`profit_loss`/`profit_loss_percent` are `null` once a holding's quantity has been fully sold down to
+zero (nothing left to have a cost basis). `error_key` is `"unreachable"` when a sync attempt couldn't
+reach CoinGecko (existing values are kept as-is), or `null` otherwise.

 ## Dashboard, Cash Flow & Reports

--- a/README.md
+++ b/README.md
@@ -64,7 +64,7 @@ Log income, expenses, and transfers across as many accounts as you want, organiz
 A live net worth timeline (30 days to all-time) aggregating cash and every manually tracked asset — investments, crypto, real estate, vehicles, precious metals — into one number, with a full breakdown by asset class, by how each asset behaves (income / neutral / drain), and by risk level.

 ### 🪙 Crypto Tracker
-A dedicated tab for the coins you actually hold — add a token and a quantity, and Aurum keeps its value current against live CoinGecko prices, no separate portfolio tracker needed. Refresh on demand with one button, or let it auto-refresh once a day; either way it plugs straight into the Net Worth engine above as just another tracked asset.
+A CoinMarketCap-style portfolio tab for the coins you actually hold: live price plus 1h/24h/7d change, your holdings value, average buy price, and profit/loss — computed from a full buy/sell history, no separate portfolio tracker needed. Refresh on demand with one button, or let it auto-refresh once a day; either way it plugs straight into the Net Worth engine above as just another tracked asset.

 ### 🎯 Budgets, Goals & Recurring Payments
 Set a monthly limit per category and watch progress bars fill up. Track savings goals with a running contribution log. Register recurring bills and post them with one click when they're due — nothing runs automatically in the background.
--- a/backend/alembic/env.py
+++ b/backend/alembic/env.py
@@ -16,6 +16,7 @@ from app.models import (  # noqa: F401 — registers metadata
    Category,
    CryptoHolding,
    CryptoSyncState,
+    CryptoTransaction,
    Goal,
    GoalContribution,
    RecurringTransaction,
--- a/backend/alembic/versions/3e3503b61b20_add_crypto_holdings.py
+++ b/backend/alembic/versions/3e3503b61b20_add_crypto_holdings.py
@@ -1,4 +1,4 @@
-"""add crypto holdings and sync state
+"""add crypto holdings, transactions, and sync state

 Revision ID: 3e3503b61b20
 Revises: f6a4d8b2e017
@@ -26,12 +26,36 @@ def upgrade() -> None:
        sa.Column('symbol', sa.String(length=20), nullable=False),
        sa.Column('name', sa.String(length=150), nullable=False),
        sa.Column('thumb_url', sa.String(length=500), nullable=True),
-        sa.Column('quantity', sa.Numeric(precision=38, scale=18), nullable=False),
+        # Cached from the last successful CoinGecko sync — quantity and
+        # average buy price are computed from crypto_transactions instead
+        # of stored here (see models/crypto.py).
+        sa.Column('last_price', sa.Numeric(precision=38, scale=18), nullable=True),
+        sa.Column('price_change_1h', sa.Numeric(precision=10, scale=4), nullable=True),
+        sa.Column('price_change_24h', sa.Numeric(precision=10, scale=4), nullable=True),
+        sa.Column('price_change_7d', sa.Numeric(precision=10, scale=4), nullable=True),
        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=False),
        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=False),
        sa.ForeignKeyConstraint(['asset_id'], ['assets.id'], ondelete='CASCADE'),
        sa.PrimaryKeyConstraint('asset_id'),
    )
+    op.create_table(
+        'crypto_transactions',
+        sa.Column('id', sa.Integer(), nullable=False),
+        sa.Column('asset_id', sa.Integer(), nullable=False),
+        sa.Column(
+            'type',
+            sa.Enum('BUY', 'SELL', name='crypto_transaction_type', native_enum=False, length=10),
+            nullable=False,
+        ),
+        sa.Column('quantity', sa.Numeric(precision=38, scale=18), nullable=False),
+        sa.Column('price_per_unit', sa.Numeric(precision=38, scale=18), nullable=False),
+        sa.Column('date', sa.Date(), nullable=False),
+        sa.Column('note', sa.Text(), nullable=True),
+        sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=False),
+        sa.Column('updated_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=False),
+        sa.ForeignKeyConstraint(['asset_id'], ['crypto_holdings.asset_id'], ondelete='CASCADE'),
+        sa.PrimaryKeyConstraint('id'),
+    )
    op.create_table(
        'crypto_sync_state',
        sa.Column('id', sa.Integer(), nullable=False),
@@ -42,4 +66,5 @@ def upgrade() -> None:

 def downgrade() -> None:
    op.drop_table('crypto_sync_state')
+    op.drop_table('crypto_transactions')
    op.drop_table('crypto_holdings')
--- a/backend/app/api/routes/crypto.py
+++ b/backend/app/api/routes/crypto.py
@@ -2,8 +2,22 @@ from fastapi import APIRouter, Depends, Query
 from sqlalchemy.ext.asyncio import AsyncSession

 from app.api.deps import get_session
-from app.schemas.crypto import CryptoHoldingCreate, CryptoHoldingRead, CryptoHoldingUpdate, CryptoSearchResult, CryptoSyncResult
-from app.services.crypto_service import create_holding, refresh_prices, search_coins, update_holding_quantity
+from app.schemas.crypto import (
+    CryptoHoldingCreate,
+    CryptoHoldingRead,
+    CryptoSearchResult,
+    CryptoSyncResult,
+    CryptoTransactionCreate,
+    CryptoTransactionRead,
+)
+from app.services.crypto_service import (
+    add_transaction,
+    create_holding,
+    delete_transaction,
+    list_transactions,
+    refresh_prices,
+    search_coins,
+)

 router = APIRouter(prefix="/crypto", tags=["crypto"])

@@ -31,11 +45,24 @@ async def create_holding_route(
    return await create_holding(session, payload)


-@router.patch("/holdings/{asset_id}", response_model=CryptoHoldingRead)
-async def update_holding_route(
-    asset_id: int, payload: CryptoHoldingUpdate, session: AsyncSession = Depends(get_session)
+@router.post("/holdings/{asset_id}/transactions", response_model=CryptoHoldingRead, status_code=201)
+async def add_transaction_route(
+    asset_id: int, payload: CryptoTransactionCreate, session: AsyncSession = Depends(get_session)
 ) -> CryptoHoldingRead:
-    return await update_holding_quantity(session, asset_id, payload.quantity)
+    """Buy more of, or sell some of, a coin already being tracked."""
+    return await add_transaction(session, asset_id, payload)
+
+
+@router.get("/holdings/{asset_id}/transactions", response_model=list[CryptoTransactionRead])
+async def list_transactions_route(
+    asset_id: int, session: AsyncSession = Depends(get_session)
+) -> list[CryptoTransactionRead]:
+    return await list_transactions(session, asset_id)
+
+
+@router.delete("/transactions/{transaction_id}", status_code=204)
+async def delete_transaction_route(transaction_id: int, session: AsyncSession = Depends(get_session)) -> None:
+    await delete_transaction(session, transaction_id)


@router.get("/search", response_model=list[CryptoSearchResult])
--- a/backend/app/models/init.py
+++ b/backend/app/models/init.py
@@ -2,7 +2,7 @@ from app.models.account import Account
 from app.models.asset import Asset, AssetValuation
 from app.models.budget import Budget
 from app.models.category import Category
-from app.models.crypto import CryptoHolding, CryptoSyncState
+from app.models.crypto import CryptoHolding, CryptoSyncState, CryptoTransaction
 from app.models.goal import Goal, GoalContribution
 from app.models.recurring import RecurringTransaction
 from app.models.settings import AppSettings
@@ -18,6 +18,7 @@ __all__ = [
    "Category",
    "CryptoHolding",
    "CryptoSyncState",
+    "CryptoTransaction",
    "Goal",
    "GoalContribution",
    "RecurringTransaction",
--- a/backend/app/models/crypto.py
+++ b/backend/app/models/crypto.py
@@ -1,17 +1,24 @@
 """Crypto holdings: a thin layer on top of the existing Asset/AssetValuation
-engine (see models/asset.py) rather than a parallel system. A CryptoHolding
-only records identity (which coin) and quantity (how much) — the actual
-value lives as ordinary AssetValuation rows, kept current by
-services/crypto_service.py, so Net Worth requires zero changes to treat a
-crypto holding like any other manually tracked asset.
+engine (see models/asset.py) rather than a parallel system. Net worth's
+number for a holding still lives as ordinary AssetValuation rows, kept
+current by services/crypto_service.py — Net Worth requires zero changes to
+treat a crypto holding like any other manually tracked asset.
+
+Quantity and average buy price are NOT stored — they're computed from the
+CryptoTransaction log (same "you record it, we derive it" shape as
+Goal/GoalContribution), because a sell doesn't just subtract quantity, it
+also has to leave the average cost basis of what's still held unchanged
+(see services/crypto_service.py's _compute_position).
 """
+from datetime import date as date_
 from datetime import datetime

-from sqlalchemy import DateTime, ForeignKey, Numeric, String
+from sqlalchemy import Date, DateTime, Enum, ForeignKey, Numeric, String, Text
 from sqlalchemy.orm import Mapped, mapped_column, relationship

 from app.db.base import Base
 from app.models.asset import Asset
+from app.models.enums import CryptoTransactionType
 from app.models.mixins import TimestampMixin


@@ -20,7 +27,8 @@ class CryptoHolding(Base, TimestampMixin):
    this table's own primary key rather than a separate id+unique
    constraint, so the relationship can never drift into a 1:many by
    accident. Deleting the Asset (the existing DELETE /assets/{id}) cascades
-    here too — there's no separate delete endpoint for a holding."""
+    here too, and cascades again to every CryptoTransaction — there's no
+    separate "delete the whole holding" endpoint."""

    __tablename__ = "crypto_holdings"

@@ -36,12 +44,43 @@ class CryptoHolding(Base, TimestampMixin):
    name: Mapped[str] = mapped_column(String(150), nullable=False)
    thumb_url: Mapped[str | None] = mapped_column(String(500), nullable=True)

-    # Bitcoin has 8 decimal places; several tokens go to 18 (wei-level
-    # amounts). Deliberately NOT Numeric(14, 2) like every money field in
-    # this app — this is a coin count, not a currency amount.
-    quantity: Mapped[Numeric] = mapped_column(Numeric(38, 18), nullable=False)
+    # Cached from the last successful sync (services/crypto_service.py) —
+    # in the app's display currency (see AppSettings.currency). Null until
+    # the first sync completes.
+    last_price: Mapped[Numeric | None] = mapped_column(Numeric(38, 18), nullable=True)
+    price_change_1h: Mapped[Numeric | None] = mapped_column(Numeric(10, 4), nullable=True)
+    price_change_24h: Mapped[Numeric | None] = mapped_column(Numeric(10, 4), nullable=True)
+    price_change_7d: Mapped[Numeric | None] = mapped_column(Numeric(10, 4), nullable=True)

    asset: Mapped["Asset"] = relationship()
+    transactions: Mapped[list["CryptoTransaction"]] = relationship(
+        back_populates="holding", cascade="all, delete-orphan", order_by="CryptoTransaction.date"
+    )
+
+
+class CryptoTransaction(Base, TimestampMixin):
+    """One buy or sell against a holding. Quantity held and average buy
+    price are both derived by replaying this log in date order — see
+    services/crypto_service.py's _compute_position for why a sell can't
+    just be "negative quantity" the way it can for a Goal contribution: it
+    must leave the remaining coins' average cost basis alone."""
+
+    __tablename__ = "crypto_transactions"
+
+    id: Mapped[int] = mapped_column(primary_key=True)
+    asset_id: Mapped[int] = mapped_column(ForeignKey("crypto_holdings.asset_id", ondelete="CASCADE"), nullable=False)
+    type: Mapped[CryptoTransactionType] = mapped_column(
+        Enum(CryptoTransactionType, name="crypto_transaction_type", native_enum=False, length=10), nullable=False
+    )
+    quantity: Mapped[Numeric] = mapped_column(Numeric(38, 18), nullable=False)
+    # Price paid (buy) or received (sell) per unit, in the app's display
+    # currency at the time of the transaction — not re-derived later, since
+    # what you actually paid doesn't change with today's market price.
+    price_per_unit: Mapped[Numeric] = mapped_column(Numeric(38, 18), nullable=False)
+    date: Mapped[date_] = mapped_column(Date, nullable=False)
+    note: Mapped[str | None] = mapped_column(Text, nullable=True)
+
+    holding: Mapped["CryptoHolding"] = relationship(back_populates="transactions")


 class CryptoSyncState(Base):
--- a/backend/app/models/enums.py
+++ b/backend/app/models/enums.py
@@ -51,6 +51,11 @@ class RecurringFrequency(str, enum.Enum):
    YEARLY = "yearly"


+class CryptoTransactionType(str, enum.Enum):
+    BUY = "buy"
+    SELL = "sell"
+
+
 class RiskLevel(str, enum.Enum):
    """Risk of loss, not asset class — set by the user, not inferred: real
    estate can be a paid-off primary home (LOW) or a leveraged rental
--- a/backend/app/schemas/backup.py
+++ b/backend/app/schemas/backup.py
@@ -10,6 +10,7 @@ from app.models.enums import (
    AssetClass,
    CapitalRole,
    CategoryKind,
+    CryptoTransactionType,
    RecurringFrequency,
    RiskLevel,
    TransactionType,
@@ -99,13 +100,30 @@ class CryptoHoldingBackup(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    # asset_id doubles as this row's own primary key (see
-    # models/crypto.py's CryptoHolding) — there's no separate `id`.
+    # models/crypto.py's CryptoHolding) — there's no separate `id`. No
+    # quantity here — it's derived from crypto_transactions below, not
+    # stored.
    asset_id: int
    coingecko_id: str
    symbol: str
    name: str
    thumb_url: str | None
+    last_price: Decimal | None = None
+    price_change_1h: Decimal | None = None
+    price_change_24h: Decimal | None = None
+    price_change_7d: Decimal | None = None
+
+
+class CryptoTransactionBackup(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: int
+    asset_id: int
+    type: CryptoTransactionType
    quantity: Decimal
+    price_per_unit: Decimal
+    date: date_
+    note: str | None


 class BudgetBackup(BaseModel):
@@ -189,6 +207,7 @@ class BackupPayload(BaseModel):
    # Defaulted so a backup exported before crypto holdings existed still
    # imports cleanly under the same format version.
    crypto_holdings: list[CryptoHoldingBackup] = Field(default_factory=list)
+    crypto_transactions: list[CryptoTransactionBackup] = Field(default_factory=list)
    # Defaulted so a backup exported before budgets existed still imports
    # cleanly under the same format version.
    budgets: list[BudgetBackup] = Field(default_factory=list)
--- a/backend/app/schemas/crypto.py
+++ b/backend/app/schemas/crypto.py
@@ -1,39 +1,74 @@
+from datetime import date as date_
 from datetime import datetime
 from decimal import Decimal
 from typing import Literal

 from pydantic import BaseModel, ConfigDict, Field

+from app.models.enums import CryptoTransactionType
+
+
+class CryptoTransactionCreate(BaseModel):
+    type: CryptoTransactionType
+    quantity: Decimal = Field(gt=0, max_digits=38, decimal_places=18)
+    # Price paid (buy) / received (sell) per unit, in the app's display
+    # currency — not fetched from CoinGecko, this is what the user actually
+    # paid, which the market price today has nothing to do with.
+    price_per_unit: Decimal = Field(gt=0, max_digits=38, decimal_places=18)
+    date: date_
+    note: str | None = Field(default=None, max_length=500)
+
+
+class CryptoTransactionRead(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: int
+    asset_id: int
+    type: CryptoTransactionType
+    quantity: Decimal
+    price_per_unit: Decimal
+    date: date_
+    note: str | None
+

 class CryptoHoldingCreate(BaseModel):
    coingecko_id: str = Field(min_length=1, max_length=100)
    symbol: str = Field(min_length=1, max_length=20)
    name: str = Field(min_length=1, max_length=150)
    thumb_url: str | None = Field(default=None, max_length=500)
-    # 18 decimal places covers wei-level token amounts; still gt=0 since a
-    # zero/negative holding isn't a holding.
-    quantity: Decimal = Field(gt=0, max_digits=38, decimal_places=18)
-
-
-class CryptoHoldingUpdate(BaseModel):
+    # A holding always starts with a buy — there's nothing to "start
+    # tracking" with a sell.
    quantity: Decimal = Field(gt=0, max_digits=38, decimal_places=18)
+    price_per_unit: Decimal = Field(gt=0, max_digits=38, decimal_places=18)
+    date: date_ = Field(default_factory=date_.today)
+    note: str | None = Field(default=None, max_length=500)


 class CryptoHoldingRead(BaseModel):
-    model_config = ConfigDict(from_attributes=True)
-
    asset_id: int
    coingecko_id: str
    symbol: str
    name: str
    thumb_url: str | None
+
+    # Quantity and avg_buy_price are derived from the transaction log (see
+    # services/crypto_service.py's _compute_position) — never stored.
    quantity: Decimal
-    # Both derived from the linked Asset's latest AssetValuation — null
-    # value/unit_price means "added but never priced yet" (CoinGecko was
-    # unreachable at creation time), not zero.
+    avg_buy_price: Decimal | None
+
+    # Cached from the last successful CoinGecko sync — null until the
+    # first one completes.
+    current_price: Decimal | None
+    price_change_1h: Decimal | None
+    price_change_24h: Decimal | None
+    price_change_7d: Decimal | None
+
+    # All derived from the above: value = current_price * quantity,
+    # cost_basis = avg_buy_price * quantity, profit_loss = value - cost_basis.
    value: Decimal | None
-    unit_price: Decimal | None
-    as_of_date: str | None
+    cost_basis: Decimal | None
+    profit_loss: Decimal | None
+    profit_loss_percent: float | None


 class CryptoSyncResult(BaseModel):
--- a/backend/app/services/backup_service.py
+++ b/backend/app/services/backup_service.py
@@ -21,7 +21,7 @@ from app.models.account import Account
 from app.models.asset import Asset, AssetValuation
 from app.models.budget import Budget
 from app.models.category import Category
-from app.models.crypto import CryptoHolding
+from app.models.crypto import CryptoHolding, CryptoTransaction
 from app.models.goal import Goal, GoalContribution
 from app.models.recurring import RecurringTransaction
 from app.models.settings import AppSettings
@@ -36,6 +36,7 @@ from app.schemas.backup import (
    BudgetBackup,
    CategoryBackup,
    CryptoHoldingBackup,
+    CryptoTransactionBackup,
    GoalBackup,
    GoalContributionBackup,
    RecurringTransactionBackup,
@@ -54,6 +55,7 @@ async def build_backup(session: AsyncSession) -> BackupPayload:
    assets = (await session.execute(select(Asset))).scalars().all()
    valuations = (await session.execute(select(AssetValuation))).scalars().all()
    crypto_holdings = (await session.execute(select(CryptoHolding))).scalars().all()
+    crypto_transactions = (await session.execute(select(CryptoTransaction))).scalars().all()
    budgets = (await session.execute(select(Budget))).scalars().all()
    goals = (await session.execute(select(Goal))).scalars().all()
    goal_contributions = (await session.execute(select(GoalContribution))).scalars().all()
@@ -76,6 +78,7 @@ async def build_backup(session: AsyncSession) -> BackupPayload:
        assets=[AssetBackup.model_validate(row) for row in assets],
        asset_valuations=[AssetValuationBackup.model_validate(row) for row in valuations],
        crypto_holdings=[CryptoHoldingBackup.model_validate(row) for row in crypto_holdings],
+        crypto_transactions=[CryptoTransactionBackup.model_validate(row) for row in crypto_transactions],
        budgets=[BudgetBackup.model_validate(row) for row in budgets],
        goals=[GoalBackup.model_validate(row) for row in goals],
        goal_contributions=[GoalContributionBackup.model_validate(row) for row in goal_contributions],
@@ -111,10 +114,15 @@ def _validate_references(payload: BackupPayload) -> None:
        if v.asset_id not in asset_ids:
            raise HTTPException(400, f"Asset valuation {v.id} references unknown asset_id {v.asset_id}")

+    crypto_holding_asset_ids = {h.asset_id for h in payload.crypto_holdings}
    for h in payload.crypto_holdings:
        if h.asset_id not in asset_ids:
            raise HTTPException(400, f"Crypto holding {h.asset_id} references unknown asset_id {h.asset_id}")

+    for tx in payload.crypto_transactions:
+        if tx.asset_id not in crypto_holding_asset_ids:
+            raise HTTPException(400, f"Crypto transaction {tx.id} references unknown asset_id {tx.asset_id}")
+
    for b in payload.budgets:
        if b.category_id not in category_ids:
            raise HTTPException(400, f"Budget {b.id} references unknown category_id {b.category_id}")
@@ -162,6 +170,7 @@ async def restore_backup(session: AsyncSession, payload: BackupPayload) -> None:
    try:
        # Children before parents.
        await session.execute(delete(AssetValuation))
+        await session.execute(delete(CryptoTransaction))
        await session.execute(delete(CryptoHolding))
        await session.execute(delete(Budget))
        await session.execute(delete(GoalContribution))
@@ -202,6 +211,7 @@ async def restore_backup(session: AsyncSession, payload: BackupPayload) -> None:

        session.add_all(AssetValuation(**row.model_dump()) for row in payload.asset_valuations)
        session.add_all(CryptoHolding(**row.model_dump()) for row in payload.crypto_holdings)
+        session.add_all(CryptoTransaction(**row.model_dump()) for row in payload.crypto_transactions)
        session.add_all(Budget(**row.model_dump()) for row in payload.budgets)
        session.add_all(Goal(**row.model_dump()) for row in payload.goals)
        session.add_all(GoalContribution(**row.model_dump()) for row in payload.goal_contributions)
@@ -220,6 +230,7 @@ async def restore_backup(session: AsyncSession, payload: BackupPayload) -> None:
        await _reset_sequence(session, "assets", payload.assets)
        await _reset_sequence(session, "transactions", payload.transactions)
        await _reset_sequence(session, "asset_valuations", payload.asset_valuations)
+        await _reset_sequence(session, "crypto_transactions", payload.crypto_transactions)
        await _reset_sequence(session, "budgets", payload.budgets)
        await _reset_sequence(session, "goals", payload.goals)
        await _reset_sequence(session, "goal_contributions", payload.goal_contributions)
--- a/backend/app/services/crypto_service.py
+++ b/backend/app/services/crypto_service.py
@@ -1,23 +1,28 @@
-"""Crypto price sync: CoinGecko Demo API calls, written into the *existing*
-Asset/AssetValuation engine (see models/asset.py) rather than a parallel
-value-tracking system. A CryptoHolding only ever records identity (which
-coin) and quantity (how much) — the actual value is an ordinary
-AssetValuation row, so Net Worth, reports, and everything else that already
-walks Asset rows needs zero changes to treat a crypto holding like any
-other manually tracked asset.
+"""Crypto price sync + position accounting: CoinGecko Demo API calls,
+written into the *existing* Asset/AssetValuation engine (see
+models/asset.py) rather than a parallel value-tracking system. A holding's
+value is an ordinary AssetValuation row, so Net Worth, reports, and
+everything else that already walks Asset rows needs zero changes to treat a
+crypto holding like any other manually tracked asset.
+
+Quantity and average buy price are never stored — they're derived from the
+CryptoTransaction log every time (see _compute_position), the same
+"you record it, we derive it" shape as Goal/GoalContribution.

 Refreshes are deliberately never automatic in the background — same
 reasoning as recurring transactions (see services/recurring_service.py):
 there's no scheduler/worker in this stack, and a rate-limited free API key
-makes "poll constantly" actively counterproductive anyway. Two triggers
-only: the "Refresh prices" button (force=True) and a lazy once-a-day check
-that piggybacks on GET /crypto/holdings (force=False) — see
-routes/crypto.py.
+makes "poll constantly" actively counterproductive anyway. Three triggers
+only: the "Refresh prices" button (force=True), a lazy once-a-day check
+that piggybacks on GET /crypto/holdings (force=False), and adding a brand
+new holding (a one-off seed fetch, justified by the explicit user action).
+Editing quantity via a buy/sell transaction never calls CoinGecko — it
+reuses the last cached price.
 """
 from datetime import date as date_
 from datetime import datetime, timedelta, timezone
 from decimal import Decimal
-from typing import Literal
+from typing import Literal, NamedTuple

 import httpx
 from fastapi import HTTPException
@@ -28,9 +33,15 @@ from sqlalchemy.orm import selectinload

 from app.core.config import get_settings
 from app.models.asset import Asset, AssetValuation
-from app.models.crypto import CryptoHolding, CryptoSyncState
-from app.models.enums import AssetClass, CapitalRole, RiskLevel
-from app.schemas.crypto import CryptoHoldingCreate, CryptoHoldingRead, CryptoSearchResult, CryptoSyncResult
+from app.models.crypto import CryptoHolding, CryptoSyncState, CryptoTransaction
+from app.models.enums import AssetClass, CapitalRole, CryptoTransactionType, RiskLevel
+from app.schemas.crypto import (
+    CryptoHoldingCreate,
+    CryptoHoldingRead,
+    CryptoSearchResult,
+    CryptoSyncResult,
+    CryptoTransactionCreate,
+)
 from app.services.settings_service import get_or_create_app_settings

 COINGECKO_BASE_URL = "https://api.coingecko.com/api/v3"
@@ -40,7 +51,7 @@ COINGECKO_BASE_URL = "https://api.coingecko.com/api/v3"
 # reason (see module docstring on why there's no background poller at all).
 AUTO_REFRESH_INTERVAL = timedelta(hours=24)

-_EAGER = (selectinload(CryptoHolding.asset).selectinload(Asset.valuations),)
+_EAGER = (selectinload(CryptoHolding.transactions),)


 def _require_api_key() -> str:
@@ -56,27 +67,51 @@ def _require_api_key() -> str:
    return api_key


-async def _fetch_prices_batch(coingecko_ids: list[str], vs_currency: str) -> dict[str, Decimal]:
-    """One CoinGecko call for every tracked coin at once (up to 515 ids per
-    call) — never one call per coin, that's what would actually burn
-    through a free-tier rate limit."""
+class _MarketPoint(NamedTuple):
+    price: Decimal
+    change_1h: Decimal | None
+    change_24h: Decimal | None
+    change_7d: Decimal | None
+
+
+def _decimal_or_none(value: object) -> Decimal | None:
+    return Decimal(str(value)) if value is not None else None
+
+
+async def _fetch_market_data(coingecko_ids: list[str], vs_currency: str) -> dict[str, _MarketPoint]:
+    """One CoinGecko call for every tracked coin at once (up to 250 ids per
+    /coins/markets call) — never one call per coin, that's what would
+    actually burn through a free-tier rate limit. Also returns 1h/24h/7d %
+    change in the same call, so this fully replaces a separate
+    /simple/price lookup."""
    if not coingecko_ids:
        return {}
    api_key = _require_api_key()
    async with httpx.AsyncClient(timeout=10.0) as client:
        response = await client.get(
-            f"{COINGECKO_BASE_URL}/simple/price",
-            params={"ids": ",".join(coingecko_ids), "vs_currencies": vs_currency},
+            f"{COINGECKO_BASE_URL}/coins/markets",
+            params={
+                "vs_currency": vs_currency,
+                "ids": ",".join(coingecko_ids),
+                "price_change_percentage": "1h,24h,7d",
+            },
            headers={"x-cg-demo-api-key": api_key},
        )
        response.raise_for_status()
        data = response.json()
-    prices: dict[str, Decimal] = {}
-    for coin_id, values in data.items():
-        price = values.get(vs_currency)
-        if price is not None:
-            prices[coin_id] = Decimal(str(price))
-    return prices
+
+    points: dict[str, _MarketPoint] = {}
+    for coin in data:
+        price = _decimal_or_none(coin.get("current_price"))
+        if price is None:
+            continue
+        points[coin["id"]] = _MarketPoint(
+            price=price,
+            change_1h=_decimal_or_none(coin.get("price_change_percentage_1h_in_currency")),
+            change_24h=_decimal_or_none(coin.get("price_change_percentage_24h_in_currency")),
+            change_7d=_decimal_or_none(coin.get("price_change_percentage_7d_in_currency")),
+        )
+    return points


 async def search_coins(query: str) -> list[CryptoSearchResult]:
@@ -103,35 +138,67 @@ async def search_coins(query: str) -> list[CryptoSearchResult]:
    ]


+def _compute_position(transactions: list[CryptoTransaction]) -> tuple[Decimal, Decimal | None]:
+    """Weighted-average-cost method, replayed over the transaction log in
+    date order: a BUY blends into the running average cost; a SELL reduces
+    quantity but leaves the average cost of what's still held unchanged —
+    selling some coins doesn't retroactively change what you paid for the
+    ones you kept. Returns (quantity, avg_buy_price); avg_buy_price is None
+    once quantity hits zero (nothing left to have a cost basis)."""
+    quantity = Decimal("0")
+    avg_price: Decimal | None = None
+    for tx in sorted(transactions, key=lambda t: (t.date, t.id)):
+        if tx.type == CryptoTransactionType.BUY:
+            existing_cost = (avg_price or Decimal("0")) * quantity
+            quantity += tx.quantity
+            avg_price = (existing_cost + tx.price_per_unit * tx.quantity) / quantity if quantity else None
+        else:
+            quantity -= tx.quantity
+            if quantity <= 0:
+                quantity = Decimal("0")
+                avg_price = None
+    return quantity, avg_price
+
+
 def _to_read(holding: CryptoHolding) -> CryptoHoldingRead:
-    latest = holding.asset.valuations[-1] if holding.asset.valuations else None
-    value = latest.value if latest else None
-    unit_price = (value / holding.quantity) if value is not None and holding.quantity else None
+    quantity, avg_buy_price = _compute_position(holding.transactions)
+    current_price = holding.last_price
+    value = current_price * quantity if current_price is not None else None
+    cost_basis = avg_buy_price * quantity if avg_buy_price is not None else None
+    profit_loss = (value - cost_basis) if value is not None and cost_basis is not None else None
+    profit_loss_percent = float(profit_loss / cost_basis * 100) if profit_loss is not None and cost_basis else None
    return CryptoHoldingRead(
        asset_id=holding.asset_id,
        coingecko_id=holding.coingecko_id,
        symbol=holding.symbol,
        name=holding.name,
        thumb_url=holding.thumb_url,
-        quantity=holding.quantity,
+        quantity=quantity,
+        avg_buy_price=avg_buy_price,
+        current_price=current_price,
+        price_change_1h=holding.price_change_1h,
+        price_change_24h=holding.price_change_24h,
+        price_change_7d=holding.price_change_7d,
        value=value,
-        unit_price=unit_price,
-        as_of_date=latest.as_of_date.isoformat() if latest else None,
+        cost_basis=cost_basis,
+        profit_loss=profit_loss,
+        profit_loss_percent=profit_loss_percent,
    )


 async def list_holdings(session: AsyncSession) -> list[CryptoHolding]:
-    # populate_existing=True: _upsert_valuation() below writes AssetValuation
-    # rows via a raw Core statement, which the ORM's identity map doesn't
-    # know happened. Without this, a session that already loaded a holding's
-    # valuations once (list_holdings gets called both before and after a
-    # refresh's writes) would keep serving the pre-refresh value here.
-    result = await session.execute(
-        select(CryptoHolding).options(*_EAGER).order_by(CryptoHolding.name).execution_options(populate_existing=True)
-    )
+    result = await session.execute(select(CryptoHolding).options(*_EAGER).order_by(CryptoHolding.name))
    return list(result.scalars().all())


+async def _get_holding_or_404(session: AsyncSession, asset_id: int) -> CryptoHolding:
+    result = await session.execute(select(CryptoHolding).options(*_EAGER).where(CryptoHolding.asset_id == asset_id))
+    holding = result.scalar_one_or_none()
+    if holding is None:
+        raise HTTPException(status_code=404, detail="Crypto holding not found")
+    return holding
+
+
 async def get_or_create_sync_state(session: AsyncSession) -> CryptoSyncState:
    state = await session.get(CryptoSyncState, 1)
    if state is None:
@@ -145,7 +212,9 @@ async def get_or_create_sync_state(session: AsyncSession) -> CryptoSyncState:
 async def _upsert_valuation(session: AsyncSession, asset_id: int, value: Decimal, as_of_date: date_) -> None:
    """Same upsert-by-date pattern as routes/assets.py's POST
    /assets/{id}/valuations — re-syncing the same day updates that day's
-    value instead of erroring."""
+    value instead of erroring. Still needed even though quantity/price
+    aren't stored on CryptoHolding: Net Worth's whole engine reads this
+    table, not CryptoHolding, for a coin's value history."""
    upsert_stmt = (
        pg_insert(AssetValuation)
        .values(asset_id=asset_id, value=value, as_of_date=as_of_date)
@@ -170,26 +239,34 @@ async def refresh_prices(session: AsyncSession, *, force: bool) -> CryptoSyncRes
    if holdings:
        settings = await get_or_create_app_settings(session)
        try:
-            prices = await _fetch_prices_batch([h.coingecko_id for h in holdings], settings.currency.lower())
+            market_data = await _fetch_market_data([h.coingecko_id for h in holdings], settings.currency.lower())
        except httpx.HTTPError:
            # CoinGecko down/rate-limited — don't touch last_synced_at (the
            # next open of the tab retries) and don't touch any existing
-            # AssetValuation. The tab still shows the last known values
-            # instead of an empty/broken page over an external outage.
+            # price/AssetValuation. The tab still shows the last known
+            # values instead of an empty/broken page over an external outage.
            error_key = "unreachable"
        else:
            today = date_.today()
            for holding in holdings:
-                price = prices.get(holding.coingecko_id)
-                if price is None:
-                    continue  # coin missing from the response — keep its last known value, don't zero it out
-                await _upsert_valuation(session, holding.asset_id, holding.quantity * price, today)
+                point = market_data.get(holding.coingecko_id)
+                if point is None:
+                    continue  # coin missing from the response — keep its last known values, don't zero them out
+                holding.last_price = point.price
+                holding.price_change_1h = point.change_1h
+                holding.price_change_24h = point.change_24h
+                holding.price_change_7d = point.change_7d
+                quantity, _ = _compute_position(holding.transactions)
+                if quantity > 0:
+                    await _upsert_valuation(session, holding.asset_id, quantity * point.price, today)

    if error_key is None:
        state.last_synced_at = now
    await session.commit()

-    holdings = await list_holdings(session)  # re-fetch so the response carries whatever was just written
+    # holdings were mutated in place above (ordinary ORM attribute
+    # assignment, not a raw Core write) — no need to re-query, they already
+    # reflect what was just committed.
    return CryptoSyncResult(
        synced=error_key is None,
        last_synced_at=state.last_synced_at,
@@ -220,18 +297,33 @@ async def create_holding(session: AsyncSession, payload: CryptoHoldingCreate) ->
        symbol=payload.symbol.upper(),
        name=payload.name,
        thumb_url=payload.thumb_url,
-        quantity=payload.quantity,
    )
    session.add(holding)

-    # Seed today's value immediately — a coin the user just added sitting at
-    # 0 until tomorrow's auto-sync would be confusing, and this one call is
-    # clearly justified by an explicit user action.
+    holding.transactions.append(
+        CryptoTransaction(
+            type=CryptoTransactionType.BUY,
+            quantity=payload.quantity,
+            price_per_unit=payload.price_per_unit,
+            date=payload.date,
+            note=payload.note,
+        )
+    )
+    await session.flush()
+
+    # Seed today's live price immediately — a coin the user just added
+    # sitting at "no price yet" until tomorrow's auto-sync would be
+    # confusing, and this one call is clearly justified by an explicit
+    # user action.
    try:
-        prices = await _fetch_prices_batch([payload.coingecko_id], settings.currency.lower())
-        price = prices.get(payload.coingecko_id)
-        if price is not None:
-            await _upsert_valuation(session, asset.id, payload.quantity * price, date_.today())
+        market_data = await _fetch_market_data([payload.coingecko_id], settings.currency.lower())
+        point = market_data.get(payload.coingecko_id)
+        if point is not None:
+            holding.last_price = point.price
+            holding.price_change_1h = point.change_1h
+            holding.price_change_24h = point.change_24h
+            holding.price_change_7d = point.change_7d
+            await _upsert_valuation(session, asset.id, payload.quantity * point.price, date_.today())
        # This counts as a real sync — bump the shared timestamp so the next
        # GET /crypto/holdings doesn't immediately re-fetch every holding
        # again a moment later (see refresh_prices' 24h window).
@@ -241,35 +333,60 @@ async def create_holding(session: AsyncSession, payload: CryptoHoldingCreate) ->
        pass  # holding is still created — the next daily/manual sync will price it

    await session.commit()
-
-    result = await session.execute(select(CryptoHolding).options(*_EAGER).where(CryptoHolding.asset_id == asset.id))
-    return _to_read(result.scalar_one())
+    return _to_read(holding)


-async def update_holding_quantity(session: AsyncSession, asset_id: int, quantity: Decimal) -> CryptoHoldingRead:
-    result = await session.execute(select(CryptoHolding).options(*_EAGER).where(CryptoHolding.asset_id == asset_id))
-    holding = result.scalar_one_or_none()
-    if holding is None:
-        raise HTTPException(status_code=404, detail="Crypto holding not found")
+async def add_transaction(session: AsyncSession, asset_id: int, payload: CryptoTransactionCreate) -> CryptoHoldingRead:
+    """A buy or sell against an existing holding — never calls CoinGecko
+    (see module docstring): value is recomputed from the last cached
+    price, same principle as the old quantity-only edit it replaces."""
+    holding = await _get_holding_or_404(session, asset_id)

-    latest = holding.asset.valuations[-1] if holding.asset.valuations else None
-    if latest is not None and holding.quantity:
-        # Recompute from the last known unit price — editing quantity must
-        # NOT call CoinGecko (see module docstring: only the button, adding
-        # a coin, and the once-a-day check are allowed to).
-        unit_price = latest.value / holding.quantity
-        await _upsert_valuation(session, asset_id, quantity * unit_price, date_.today())
+    if payload.type == CryptoTransactionType.SELL:
+        current_quantity, _ = _compute_position(holding.transactions)
+        if payload.quantity > current_quantity:
+            raise HTTPException(status_code=400, detail="Cannot sell more than you currently hold")

-    holding.quantity = quantity
-    await session.commit()
-
-    # populate_existing=True — see list_holdings()'s comment: the AssetValuation
-    # loaded above (before _upsert_valuation's raw Core write) is otherwise
-    # served stale here.
-    result = await session.execute(
-        select(CryptoHolding)
-        .options(*_EAGER)
-        .where(CryptoHolding.asset_id == asset_id)
-        .execution_options(populate_existing=True)
+    holding.transactions.append(
+        CryptoTransaction(
+            type=payload.type,
+            quantity=payload.quantity,
+            price_per_unit=payload.price_per_unit,
+            date=payload.date,
+            note=payload.note,
+        )
    )
-    return _to_read(result.scalar_one())
+    await session.flush()
+
+    quantity, _ = _compute_position(holding.transactions)
+    if holding.last_price is not None:
+        await _upsert_valuation(session, asset_id, quantity * holding.last_price, date_.today())
+
+    await session.commit()
+    return _to_read(holding)
+
+
+async def list_transactions(session: AsyncSession, asset_id: int) -> list[CryptoTransaction]:
+    await _get_holding_or_404(session, asset_id)  # 404s if the holding itself doesn't exist
+    result = await session.execute(
+        select(CryptoTransaction)
+        .where(CryptoTransaction.asset_id == asset_id)
+        .order_by(CryptoTransaction.date.desc(), CryptoTransaction.id.desc())
+    )
+    return list(result.scalars().all())
+
+
+async def delete_transaction(session: AsyncSession, transaction_id: int) -> None:
+    transaction = await session.get(CryptoTransaction, transaction_id)
+    if transaction is None:
+        raise HTTPException(status_code=404, detail="Crypto transaction not found")
+    asset_id = transaction.asset_id
+    await session.delete(transaction)
+    await session.flush()
+
+    holding = await _get_holding_or_404(session, asset_id)
+    quantity, _ = _compute_position(holding.transactions)
+    if holding.last_price is not None:
+        await _upsert_valuation(session, asset_id, quantity * holding.last_price, date_.today())
+
+    await session.commit()
--- a/backend/tests/test_crypto.py
+++ b/backend/tests/test_crypto.py
@@ -1,7 +1,7 @@
-"""Crypto holdings: creation, quantity updates, and the lazy/forced price
-sync. CoinGecko itself is never called in tests —
-services/crypto_service.py's _fetch_prices_batch is monkeypatched with a
-canned price feed instead, same way any external dependency would be.
+"""Crypto holdings: buy/sell transaction log, weighted-average cost basis,
+and the lazy/forced price sync. CoinGecko itself is never called in tests —
+services/crypto_service.py's _fetch_market_data is monkeypatched with a
+canned market-data feed instead, same way any external dependency would be.
 """
 from decimal import Decimal

@@ -12,35 +12,56 @@ from app.services import crypto_service
 from tests.helpers import money


-async def _add_bitcoin(client: AsyncClient, quantity: str = "0.5") -> dict:
-    resp = await client.post(
-        "/crypto/holdings",
-        json={"coingecko_id": "bitcoin", "symbol": "btc", "name": "Bitcoin", "quantity": quantity},
+def _point(price: str, change_1h: str | None = None, change_24h: str | None = None, change_7d: str | None = None):
+    return crypto_service._MarketPoint(
+        price=Decimal(price),
+        change_1h=Decimal(change_1h) if change_1h else None,
+        change_24h=Decimal(change_24h) if change_24h else None,
+        change_7d=Decimal(change_7d) if change_7d else None,
    )
-    assert resp.status_code == 201
-    return resp.json()


-def _fake_fetch(prices: dict[str, Decimal]):
+def _fake_fetch(prices: dict[str, "crypto_service._MarketPoint"]):
    async def fetch(coingecko_ids, vs_currency):
        return {cid: prices[cid] for cid in coingecko_ids if cid in prices}

    return fetch


-async def test_create_holding_seeds_todays_value_immediately(client: AsyncClient, monkeypatch):
-    monkeypatch.setattr(crypto_service, "_fetch_prices_batch", _fake_fetch({"bitcoin": Decimal("50000")}))
+async def _add_bitcoin(client: AsyncClient, quantity: str = "0.5", price_per_unit: str = "40000") -> dict:
+    resp = await client.post(
+        "/crypto/holdings",
+        json={
+            "coingecko_id": "bitcoin",
+            "symbol": "btc",
+            "name": "Bitcoin",
+            "quantity": quantity,
+            "price_per_unit": price_per_unit,
+            "date": "2026-01-01",
+        },
+    )
+    assert resp.status_code == 201, resp.text
+    return resp.json()

-    holding = await _add_bitcoin(client, "0.5")
+
+async def test_create_holding_seeds_todays_value_and_position_immediately(client: AsyncClient, monkeypatch):
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", _fake_fetch({"bitcoin": _point("50000")}))
+
+    holding = await _add_bitcoin(client, "0.5", "40000")

    assert holding["symbol"] == "BTC"  # normalized to uppercase
+    assert money(holding["quantity"]) == money("0.5")
+    assert money(holding["avg_buy_price"]) == money("40000")
+    assert money(holding["current_price"]) == money("50000")
    assert money(holding["value"]) == money("25000")  # 0.5 * 50000
-    assert money(holding["unit_price"]) == money("50000")
+    assert money(holding["cost_basis"]) == money("20000")  # 0.5 * 40000
+    assert money(holding["profit_loss"]) == money("5000")
+    assert round(holding["profit_loss_percent"], 2) == 25.0


 async def test_holding_shows_up_in_net_worth_breakdown(client: AsyncClient, monkeypatch):
-    monkeypatch.setattr(crypto_service, "_fetch_prices_batch", _fake_fetch({"bitcoin": Decimal("50000")}))
-    await _add_bitcoin(client, "1")
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", _fake_fetch({"bitcoin": _point("50000")}))
+    await _add_bitcoin(client, "1", "40000")

    resp = await client.get("/net-worth/summary")

@@ -48,23 +69,96 @@ async def test_holding_shows_up_in_net_worth_breakdown(client: AsyncClient, monk
    assert money(breakdown["crypto"]["amount"]) == money("50000")


-async def test_update_quantity_recomputes_value_without_calling_coingecko(client: AsyncClient, monkeypatch):
-    monkeypatch.setattr(crypto_service, "_fetch_prices_batch", _fake_fetch({"bitcoin": Decimal("50000")}))
-    holding = await _add_bitcoin(client, "0.5")
+async def test_second_buy_blends_into_weighted_average_cost(client: AsyncClient, monkeypatch):
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", _fake_fetch({"bitcoin": _point("50000")}))
+    holding = await _add_bitcoin(client, "1", "40000")  # cost basis: 40000

    async def fail_if_called(coingecko_ids, vs_currency):
-        raise AssertionError("updating quantity must not call CoinGecko")
+        raise AssertionError("adding a transaction must not call CoinGecko")

-    monkeypatch.setattr(crypto_service, "_fetch_prices_batch", fail_if_called)
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", fail_if_called)

-    resp = await client.patch(f"/crypto/holdings/{holding['asset_id']}", json={"quantity": "2"})
+    resp = await client.post(
+        f"/crypto/holdings/{holding['asset_id']}/transactions",
+        json={"type": "buy", "quantity": "1", "price_per_unit": "60000", "date": "2026-02-01"},
+    )
+
+    assert resp.status_code == 201, resp.text
+    body = resp.json()
+    assert money(body["quantity"]) == money("2")
+    # (1*40000 + 1*60000) / 2 = 50000
+    assert money(body["avg_buy_price"]) == money("50000")
+    assert money(body["value"]) == money("100000")  # 2 * 50000 (last known price, unchanged)
+
+
+async def test_sell_reduces_quantity_but_not_the_average_cost_of_what_remains(client: AsyncClient, monkeypatch):
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", _fake_fetch({"bitcoin": _point("50000")}))
+    holding = await _add_bitcoin(client, "2", "40000")  # avg cost 40000
+
+    resp = await client.post(
+        f"/crypto/holdings/{holding['asset_id']}/transactions",
+        json={"type": "sell", "quantity": "1", "price_per_unit": "55000", "date": "2026-02-01"},
+    )
+
+    assert resp.status_code == 201, resp.text
+    body = resp.json()
+    assert money(body["quantity"]) == money("1")
+    assert money(body["avg_buy_price"]) == money("40000")  # unchanged by the sell
+    assert money(body["value"]) == money("50000")  # 1 * 50000
+
+
+async def test_selling_more_than_held_is_rejected(client: AsyncClient, monkeypatch):
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", _fake_fetch({"bitcoin": _point("50000")}))
+    holding = await _add_bitcoin(client, "1", "40000")
+
+    resp = await client.post(
+        f"/crypto/holdings/{holding['asset_id']}/transactions",
+        json={"type": "sell", "quantity": "2", "price_per_unit": "55000", "date": "2026-02-01"},
+    )
+
+    assert resp.status_code == 400
+
+
+async def test_deleting_a_transaction_recomputes_the_position(client: AsyncClient, monkeypatch):
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", _fake_fetch({"bitcoin": _point("50000")}))
+    holding = await _add_bitcoin(client, "1", "40000")
+
+    second = await client.post(
+        f"/crypto/holdings/{holding['asset_id']}/transactions",
+        json={"type": "buy", "quantity": "1", "price_per_unit": "60000", "date": "2026-02-01"},
+    )
+    tx_id = next(
+        t["id"]
+        for t in (await client.get(f"/crypto/holdings/{holding['asset_id']}/transactions")).json()
+        if t["price_per_unit"] == "60000.000000000000000000"
+    )
+    assert second.json()["quantity"] == "2.000000000000000000"
+
+    resp = await client.delete(f"/crypto/transactions/{tx_id}")
+    assert resp.status_code == 204
+
+    refreshed = (await client.get("/crypto/holdings")).json()["holdings"][0]
+    assert money(refreshed["quantity"]) == money("1")
+    assert money(refreshed["avg_buy_price"]) == money("40000")
+
+
+async def test_transaction_history_lists_newest_first(client: AsyncClient, monkeypatch):
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", _fake_fetch({"bitcoin": _point("50000")}))
+    holding = await _add_bitcoin(client, "1", "40000", )
+    await client.post(
+        f"/crypto/holdings/{holding['asset_id']}/transactions",
+        json={"type": "buy", "quantity": "1", "price_per_unit": "60000", "date": "2026-02-01"},
+    )
+
+    resp = await client.get(f"/crypto/holdings/{holding['asset_id']}/transactions")

    assert resp.status_code == 200
-    assert money(resp.json()["value"]) == money("100000")  # 2 * 50000 (last known price)
+    dates = [t["date"] for t in resp.json()]
+    assert dates == ["2026-02-01", "2026-01-01"]


 async def test_deleting_the_asset_removes_the_crypto_holding_too(client: AsyncClient, monkeypatch):
-    monkeypatch.setattr(crypto_service, "_fetch_prices_batch", _fake_fetch({"bitcoin": Decimal("50000")}))
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", _fake_fetch({"bitcoin": _point("50000")}))
    holding = await _add_bitcoin(client)

    resp = await client.delete(f"/assets/{holding['asset_id']}")
@@ -75,7 +169,7 @@ async def test_deleting_the_asset_removes_the_crypto_holding_too(client: AsyncCl


 async def test_get_holdings_does_not_resync_within_24_hours(client: AsyncClient, monkeypatch):
-    monkeypatch.setattr(crypto_service, "_fetch_prices_batch", _fake_fetch({"bitcoin": Decimal("50000")}))
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", _fake_fetch({"bitcoin": _point("50000")}))
    await _add_bitcoin(client)

    calls: list[list[str]] = []
@@ -84,7 +178,7 @@ async def test_get_holdings_does_not_resync_within_24_hours(client: AsyncClient,
        calls.append(coingecko_ids)
        return {}

-    monkeypatch.setattr(crypto_service, "_fetch_prices_batch", counting_fetch)
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", counting_fetch)

    resp = await client.get("/crypto/holdings")

@@ -92,33 +186,37 @@ async def test_get_holdings_does_not_resync_within_24_hours(client: AsyncClient,
    assert calls == []  # creation's own sync already satisfied the 24h window


-async def test_manual_refresh_button_bypasses_the_24h_window(client: AsyncClient, monkeypatch):
-    monkeypatch.setattr(crypto_service, "_fetch_prices_batch", _fake_fetch({"bitcoin": Decimal("50000")}))
-    await _add_bitcoin(client)
+async def test_manual_refresh_button_bypasses_the_24h_window_and_updates_changes(client: AsyncClient, monkeypatch):
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", _fake_fetch({"bitcoin": _point("50000")}))
+    await _add_bitcoin(client, "0.5", "40000")

    calls: list[list[str]] = []

    async def counting_fetch(coingecko_ids, vs_currency):
        calls.append(coingecko_ids)
-        return {"bitcoin": Decimal("60000")}
+        return {"bitcoin": _point("60000", change_1h="0.5", change_24h="2.1", change_7d="-3.4")}

-    monkeypatch.setattr(crypto_service, "_fetch_prices_batch", counting_fetch)
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", counting_fetch)

    resp = await client.post("/crypto/refresh")

    assert resp.json()["synced"] is True
    assert calls == [["bitcoin"]]
-    assert money(resp.json()["holdings"][0]["value"]) == money("30000")  # 0.5 * 60000
+    holding = resp.json()["holdings"][0]
+    assert money(holding["value"]) == money("30000")  # 0.5 * 60000
+    assert money(holding["price_change_1h"]) == money("0.5")
+    assert money(holding["price_change_24h"]) == money("2.1")
+    assert money(holding["price_change_7d"]) == money("-3.4")


 async def test_coingecko_outage_keeps_last_known_value_instead_of_failing(client: AsyncClient, monkeypatch):
-    monkeypatch.setattr(crypto_service, "_fetch_prices_batch", _fake_fetch({"bitcoin": Decimal("50000")}))
-    await _add_bitcoin(client)
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", _fake_fetch({"bitcoin": _point("50000")}))
+    await _add_bitcoin(client, "0.5", "40000")

    async def broken_fetch(coingecko_ids, vs_currency):
        raise httpx.ConnectError("simulated outage")

-    monkeypatch.setattr(crypto_service, "_fetch_prices_batch", broken_fetch)
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", broken_fetch)

    resp = await client.post("/crypto/refresh")

@@ -134,36 +232,42 @@ async def test_create_rejects_when_no_api_key_configured(client: AsyncClient, mo

    resp = await client.post(
        "/crypto/holdings",
-        json={"coingecko_id": "bitcoin", "symbol": "btc", "name": "Bitcoin", "quantity": "0.5"},
+        json={
+            "coingecko_id": "bitcoin",
+            "symbol": "btc",
+            "name": "Bitcoin",
+            "quantity": "0.5",
+            "price_per_unit": "40000",
+            "date": "2026-01-01",
+        },
    )

    assert resp.status_code == 400


-async def test_backup_roundtrip_preserves_the_holding_not_just_the_asset(client: AsyncClient, monkeypatch):
+async def test_backup_roundtrip_preserves_holding_and_transaction_log(client: AsyncClient, monkeypatch):
    """A crypto holding is an Asset underneath, so it would still show up
    after a restore even without this — but as an inert manual asset,
-    having silently lost which coin it was and how much was held. Backup
-    must carry the CryptoHolding row too, not just Asset/AssetValuation."""
-    monkeypatch.setattr(crypto_service, "_fetch_prices_batch", _fake_fetch({"bitcoin": Decimal("50000")}))
-    holding = await _add_bitcoin(client, "0.5")
+    having silently lost which coin it was and its whole buy/sell history
+    (so quantity and avg buy price couldn't be recomputed). Backup must
+    carry both CryptoHolding and CryptoTransaction rows."""
+    monkeypatch.setattr(crypto_service, "_fetch_market_data", _fake_fetch({"bitcoin": _point("50000")}))
+    holding = await _add_bitcoin(client, "1", "40000")
+    await client.post(
+        f"/crypto/holdings/{holding['asset_id']}/transactions",
+        json={"type": "buy", "quantity": "1", "price_per_unit": "60000", "date": "2026-02-01"},
+    )

    payload = (await client.get("/backup/export")).json()
    assert len(payload["crypto_holdings"]) == 1
-    backed_up = payload["crypto_holdings"][0]
-    assert backed_up["asset_id"] == holding["asset_id"]
-    assert backed_up["coingecko_id"] == "bitcoin"
-    assert backed_up["symbol"] == "BTC"
-    assert backed_up["name"] == "Bitcoin"
-    assert backed_up["thumb_url"] is None
-    assert money(backed_up["quantity"]) == money("0.5")
+    assert len(payload["crypto_transactions"]) == 2

    import_resp = await client.post("/backup/import", json=payload)
    assert import_resp.status_code == 200, import_resp.text

-    resp = await client.get("/crypto/holdings")
-    restored = resp.json()["holdings"]
-    assert len(restored) == 1
-    assert restored[0]["coingecko_id"] == "bitcoin"
-    assert restored[0]["asset_id"] == holding["asset_id"]
-    assert money(restored[0]["value"]) == money("25000")  # AssetValuation history survives too
+    restored = (await client.get("/crypto/holdings")).json()["holdings"][0]
+    assert restored["coingecko_id"] == "bitcoin"
+    assert restored["asset_id"] == holding["asset_id"]
+    assert money(restored["quantity"]) == money("2")
+    assert money(restored["avg_buy_price"]) == money("50000")
+    assert money(restored["value"]) == money("100000")  # last_price survived too (2 * 50000)
--- a/frontend/src/api/crypto.ts
+++ b/frontend/src/api/crypto.ts
@@ -1,5 +1,12 @@
 import { api } from "@/api/client";
-import type { CryptoHolding, CryptoHoldingInput, CryptoSearchResult, CryptoSyncResult } from "@/types";
+import type {
+  CryptoHolding,
+  CryptoHoldingCreateInput,
+  CryptoSearchResult,
+  CryptoSyncResult,
+  CryptoTransaction,
+  CryptoTransactionInput,
+} from "@/types";

 // Also triggers the lazy once-a-day auto-refresh server-side — see
 // services/crypto_service.py.
@@ -11,16 +18,26 @@ export function refreshCryptoPrices() {
  return api.post<CryptoSyncResult>("/crypto/refresh", {});
 }

-export function createCryptoHolding(input: CryptoHoldingInput) {
+export function createCryptoHolding(input: CryptoHoldingCreateInput) {
  return api.post<CryptoHolding>("/crypto/holdings", input);
 }

-export function updateCryptoHoldingQuantity(assetId: number, quantity: string) {
-  return api.patch<CryptoHolding>(`/crypto/holdings/${assetId}`, { quantity });
+// Buy more of, or sell some of, a coin already being tracked.
+export function addCryptoTransaction(assetId: number, input: CryptoTransactionInput) {
+  return api.post<CryptoHolding>(`/crypto/holdings/${assetId}/transactions`, input);
+}
+
+export function fetchCryptoTransactions(assetId: number) {
+  return api.get<CryptoTransaction[]>(`/crypto/holdings/${assetId}/transactions`);
+}
+
+export function deleteCryptoTransaction(transactionId: number) {
+  return api.delete<void>(`/crypto/transactions/${transactionId}`);
 }

 // Reuses the existing asset-delete endpoint — deleting the Asset cascades
-// to the linked crypto_holdings row server-side, no dedicated endpoint.
+// to the linked crypto_holdings row (and its whole transaction log)
+// server-side, no dedicated endpoint.
 export function deleteCryptoHolding(assetId: number) {
  return api.delete<void>(`/assets/${assetId}`);
 }
--- a/frontend/src/components/crypto/CryptoAddModal.tsx
+++ b/frontend/src/components/crypto/CryptoAddModal.tsx
@@ -26,6 +26,8 @@ export function CryptoAddModal({ open, onClose }: CryptoAddModalProps) {
  const [searchError, setSearchError] = useState<string | null>(null);
  const [selected, setSelected] = useState<CryptoSearchResult | null>(null);
  const [quantity, setQuantity] = useState("");
+  const [pricePerUnit, setPricePerUnit] = useState("");
+  const [date, setDate] = useState(() => new Date().toISOString().slice(0, 10));
  const [saveError, setSaveError] = useState<string | null>(null);

  useEffect(() => {
@@ -34,6 +36,8 @@ export function CryptoAddModal({ open, onClose }: CryptoAddModalProps) {
    setResults([]);
    setSelected(null);
    setQuantity("");
+    setPricePerUnit("");
+    setDate(new Date().toISOString().slice(0, 10));
    setSearchError(null);
    setSaveError(null);
  }, [open]);
@@ -74,6 +78,8 @@ export function CryptoAddModal({ open, onClose }: CryptoAddModalProps) {
        name: selected.name,
        thumb_url: selected.thumb_url,
        quantity,
+        price_per_unit: pricePerUnit,
+        date,
      });
      onClose();
    } catch {
@@ -139,17 +145,42 @@ export function CryptoAddModal({ open, onClose }: CryptoAddModalProps) {
            </span>
          </div>

+          <div className="grid grid-cols-2 gap-3">
+            <div>
+              <Label htmlFor="crypto-quantity">{t("crypto.form.quantityLabel")}</Label>
+              <Input
+                id="crypto-quantity"
+                type="number"
+                step="any"
+                min="0"
+                required
+                autoFocus
+                value={quantity}
+                onChange={(event) => setQuantity(event.target.value)}
+              />
+            </div>
+            <div>
+              <Label htmlFor="crypto-price">{t("crypto.form.pricePerUnitLabel")}</Label>
+              <Input
+                id="crypto-price"
+                type="number"
+                step="any"
+                min="0"
+                required
+                value={pricePerUnit}
+                onChange={(event) => setPricePerUnit(event.target.value)}
+              />
+            </div>
+          </div>
+
          <div>
-            <Label htmlFor="crypto-quantity">{t("crypto.form.quantityLabel")}</Label>
+            <Label htmlFor="crypto-date">{t("crypto.form.dateLabel")}</Label>
            <Input
-              id="crypto-quantity"
-              type="number"
-              step="any"
-              min="0"
+              id="crypto-date"
+              type="date"
              required
-              autoFocus
-              value={quantity}
-              onChange={(event) => setQuantity(event.target.value)}
+              value={date}
+              onChange={(event) => setDate(event.target.value)}
            />
          </div>

--- a/frontend/src/components/crypto/CryptoEditModal.tsx
+++ b/frontend/src/components/crypto/CryptoEditModal.tsx
@@ -1,75 +0,0 @@
-import { type FormEvent, useEffect, useState } from "react";
-import { Button } from "@/components/ui/Button";
-import { Dialog } from "@/components/ui/Dialog";
-import { Input, Label } from "@/components/ui/Input";
-import { useUpdateCryptoHoldingQuantity } from "@/hooks/useCrypto";
-import { useTranslation } from "@/lib/i18n";
-import type { CryptoHolding } from "@/types";
-
-interface CryptoEditModalProps {
-  open: boolean;
-  onClose: () => void;
-  holding: CryptoHolding | null;
-}
-
-/** Quantity only — editing never calls CoinGecko (see
- * services/crypto_service.py's update_holding_quantity): the value is
- * recomputed from the last known price instead. */
-export function CryptoEditModal({ open, onClose, holding }: CryptoEditModalProps) {
-  const { t } = useTranslation();
-  const updateQuantity = useUpdateCryptoHoldingQuantity();
-
-  const [quantity, setQuantity] = useState("");
-  const [error, setError] = useState<string | null>(null);
-
-  useEffect(() => {
-    if (!open || !holding) return;
-    setQuantity(holding.quantity);
-    setError(null);
-  }, [open, holding]);
-
-  async function handleSubmit(event: FormEvent) {
-    event.preventDefault();
-    if (!holding) return;
-    setError(null);
-    try {
-      await updateQuantity.mutateAsync({ assetId: holding.asset_id, quantity });
-      onClose();
-    } catch {
-      setError(t("crypto.form.saveError"));
-    }
-  }
-
-  if (!holding) return null;
-
-  return (
-    <Dialog open={open} onClose={onClose} title={t("crypto.form.editTitle", { name: holding.name })}>
-      <form onSubmit={handleSubmit} className="space-y-3">
-        <div>
-          <Label htmlFor="crypto-edit-quantity">{t("crypto.form.quantityLabel")}</Label>
-          <Input
-            id="crypto-edit-quantity"
-            type="number"
-            step="any"
-            min="0"
-            required
-            autoFocus
-            value={quantity}
-            onChange={(event) => setQuantity(event.target.value)}
-          />
-        </div>
-
-        {error && <p className="text-sm text-danger">{error}</p>}
-
-        <div className="flex justify-end gap-2 pt-2">
-          <Button type="button" variant="ghost" onClick={onClose}>
-            {t("common.cancel")}
-          </Button>
-          <Button type="submit" disabled={updateQuantity.isPending}>
-            {updateQuantity.isPending ? t("common.saving") : t("common.save")}
-          </Button>
-        </div>
-      </form>
-    </Dialog>
-  );
-}
--- a/frontend/src/components/crypto/CryptoHoldingsList.tsx
+++ b/frontend/src/components/crypto/CryptoHoldingsList.tsx
@@ -1,64 +0,0 @@
-import { Bitcoin, Pencil, Trash2 } from "lucide-react";
-import { formatCurrency } from "@/lib/format";
-import { useTranslation } from "@/lib/i18n";
-import type { CryptoHolding } from "@/types";
-
-interface CryptoHoldingsListProps {
-  items: CryptoHolding[];
-  onEdit: (holding: CryptoHolding) => void;
-  onDelete: (holding: CryptoHolding) => void;
-}
-
-export function CryptoHoldingsList({ items, onEdit, onDelete }: CryptoHoldingsListProps) {
-  const { t } = useTranslation();
-
-  if (items.length === 0) {
-    return <p className="py-10 text-center text-sm text-text-muted">{t("crypto.empty")}</p>;
-  }
-
-  return (
-    <ul className="divide-y divide-gridline">
-      {items.map((holding) => (
-        <li key={holding.asset_id} className="flex items-center gap-3 py-3">
-          {holding.thumb_url ? (
-            <img src={holding.thumb_url} alt="" className="h-9 w-9 shrink-0 rounded-full" />
-          ) : (
-            <span className="flex h-9 w-9 shrink-0 items-center justify-center rounded-full bg-surface-2">
-              <Bitcoin size={16} className="text-text-secondary" />
-            </span>
-          )}
-          <span className="min-w-0 flex-1">
-            <span className="block truncate text-sm font-medium text-text-primary">{holding.name}</span>
-            <span className="block truncate text-xs text-text-muted">
-              {Number(holding.quantity)} {holding.symbol}
-              {holding.unit_price !== null && ` · ${formatCurrency(holding.unit_price)}`}
-            </span>
-          </span>
-          <span className="shrink-0 text-right">
-            <span className="block text-sm font-medium tabular-nums text-text-primary">
-              {holding.value !== null ? formatCurrency(holding.value) : t("crypto.pendingPrice")}
-            </span>
-          </span>
-          <span className="flex shrink-0 gap-1">
-            <button
-              type="button"
-              aria-label={t("common.edit")}
-              onClick={() => onEdit(holding)}
-              className="rounded-md p-1.5 text-text-muted hover:bg-surface-2 hover:text-text-primary"
-            >
-              <Pencil size={15} />
-            </button>
-            <button
-              type="button"
-              aria-label={t("common.delete")}
-              onClick={() => onDelete(holding)}
-              className="rounded-md p-1.5 text-text-muted hover:bg-surface-2 hover:text-danger"
-            >
-              <Trash2 size={15} />
-            </button>
-          </span>
-        </li>
-      ))}
-    </ul>
-  );
-}
--- a/frontend/src/components/crypto/CryptoHoldingsTable.tsx
+++ b/frontend/src/components/crypto/CryptoHoldingsTable.tsx
@@ -0,0 +1,151 @@
+import { Bitcoin, History, Plus, Trash2 } from "lucide-react";
+import { formatCurrency } from "@/lib/format";
+import { useTranslation } from "@/lib/i18n";
+import type { CryptoHolding } from "@/types";
+
+interface CryptoHoldingsTableProps {
+  items: CryptoHolding[];
+  onTrade: (holding: CryptoHolding) => void;
+  onViewHistory: (holding: CryptoHolding) => void;
+  onDelete: (holding: CryptoHolding) => void;
+}
+
+function PercentCell({ value }: { value: string | null }) {
+  if (value === null) return <span className="text-text-muted">—</span>;
+  const num = Number(value);
+  const color = num > 0 ? "var(--success)" : num < 0 ? "var(--danger)" : "var(--text-muted)";
+  return (
+    <span className="tabular-nums" style={{ color }}>
+      {num > 0 ? "+" : ""}
+      {num.toFixed(2)}%
+    </span>
+  );
+}
+
+export function CryptoHoldingsTable({ items, onTrade, onViewHistory, onDelete }: CryptoHoldingsTableProps) {
+  const { t } = useTranslation();
+
+  if (items.length === 0) {
+    return <p className="py-10 text-center text-sm text-text-muted">{t("crypto.empty")}</p>;
+  }
+
+  return (
+    <div className="overflow-x-auto">
+      <table className="w-full min-w-[860px] text-sm">
+        <thead>
+          <tr className="border-b border-border text-left text-xs text-text-muted">
+            <th className="py-2 pr-3 font-medium">{t("crypto.table.name")}</th>
+            <th className="py-2 pr-3 text-right font-medium">{t("crypto.table.price")}</th>
+            <th className="py-2 pr-3 text-right font-medium">{t("crypto.table.change1h")}</th>
+            <th className="py-2 pr-3 text-right font-medium">{t("crypto.table.change24h")}</th>
+            <th className="py-2 pr-3 text-right font-medium">{t("crypto.table.change7d")}</th>
+            <th className="py-2 pr-3 text-right font-medium">{t("crypto.table.holdings")}</th>
+            <th className="py-2 pr-3 text-right font-medium">{t("crypto.table.avgBuyPrice")}</th>
+            <th className="py-2 pr-3 text-right font-medium">{t("crypto.table.profitLoss")}</th>
+            <th className="py-2 pl-3 text-right font-medium">{t("crypto.table.actions")}</th>
+          </tr>
+        </thead>
+        <tbody className="divide-y divide-gridline">
+          {items.map((holding) => {
+            const profitColor =
+              holding.profit_loss === null
+                ? undefined
+                : Number(holding.profit_loss) > 0
+                  ? "var(--success)"
+                  : Number(holding.profit_loss) < 0
+                    ? "var(--danger)"
+                    : "var(--text-muted)";
+            const sign = holding.profit_loss !== null && Number(holding.profit_loss) > 0 ? "+" : "";
+
+            return (
+              <tr key={holding.asset_id}>
+                <td className="py-3 pr-3">
+                  <div className="flex items-center gap-2.5">
+                    {holding.thumb_url ? (
+                      <img src={holding.thumb_url} alt="" className="h-7 w-7 shrink-0 rounded-full" />
+                    ) : (
+                      <span className="flex h-7 w-7 shrink-0 items-center justify-center rounded-full bg-surface-2">
+                        <Bitcoin size={14} className="text-text-secondary" />
+                      </span>
+                    )}
+                    <span className="min-w-0">
+                      <span className="block truncate text-sm font-medium text-text-primary">{holding.name}</span>
+                      <span className="block text-xs text-text-muted">{holding.symbol}</span>
+                    </span>
+                  </div>
+                </td>
+                <td className="py-3 pr-3 text-right tabular-nums text-text-primary">
+                  {holding.current_price !== null ? formatCurrency(holding.current_price) : t("crypto.pendingPrice")}
+                </td>
+                <td className="py-3 pr-3 text-right">
+                  <PercentCell value={holding.price_change_1h} />
+                </td>
+                <td className="py-3 pr-3 text-right">
+                  <PercentCell value={holding.price_change_24h} />
+                </td>
+                <td className="py-3 pr-3 text-right">
+                  <PercentCell value={holding.price_change_7d} />
+                </td>
+                <td className="py-3 pr-3 text-right">
+                  <span className="block tabular-nums text-text-primary">
+                    {holding.value !== null ? formatCurrency(holding.value) : t("crypto.pendingPrice")}
+                  </span>
+                  <span className="block text-xs tabular-nums text-text-muted">
+                    {Number(holding.quantity)} {holding.symbol}
+                  </span>
+                </td>
+                <td className="py-3 pr-3 text-right tabular-nums text-text-primary">
+                  {holding.avg_buy_price !== null ? formatCurrency(holding.avg_buy_price) : "—"}
+                </td>
+                <td className="py-3 pr-3 text-right">
+                  {holding.profit_loss !== null && holding.profit_loss_percent !== null ? (
+                    <>
+                      <span className="block tabular-nums" style={{ color: profitColor }}>
+                        {sign}
+                        {formatCurrency(holding.profit_loss)}
+                      </span>
+                      <span className="block text-xs tabular-nums" style={{ color: profitColor }}>
+                        {sign}
+                        {holding.profit_loss_percent.toFixed(2)}%
+                      </span>
+                    </>
+                  ) : (
+                    <span className="text-text-muted">—</span>
+                  )}
+                </td>
+                <td className="py-3 pl-3">
+                  <div className="flex justify-end gap-1">
+                    <button
+                      type="button"
+                      aria-label={t("crypto.form.tradeButton")}
+                      onClick={() => onTrade(holding)}
+                      className="rounded-md p-1.5 text-text-muted hover:bg-surface-2 hover:text-text-primary"
+                    >
+                      <Plus size={15} />
+                    </button>
+                    <button
+                      type="button"
+                      aria-label={t("crypto.history.viewButton")}
+                      onClick={() => onViewHistory(holding)}
+                      className="rounded-md p-1.5 text-text-muted hover:bg-surface-2 hover:text-text-primary"
+                    >
+                      <History size={15} />
+                    </button>
+                    <button
+                      type="button"
+                      aria-label={t("common.delete")}
+                      onClick={() => onDelete(holding)}
+                      className="rounded-md p-1.5 text-text-muted hover:bg-surface-2 hover:text-danger"
+                    >
+                      <Trash2 size={15} />
+                    </button>
+                  </div>
+                </td>
+              </tr>
+            );
+          })}
+        </tbody>
+      </table>
+    </div>
+  );
+}
--- a/frontend/src/components/crypto/CryptoTransactionHistoryModal.tsx
+++ b/frontend/src/components/crypto/CryptoTransactionHistoryModal.tsx
@@ -0,0 +1,69 @@
+import { Trash2 } from "lucide-react";
+import { Dialog } from "@/components/ui/Dialog";
+import { useCryptoTransactions, useDeleteCryptoTransaction } from "@/hooks/useCrypto";
+import { formatCurrency, formatTransactionDate } from "@/lib/format";
+import { useTranslation } from "@/lib/i18n";
+import type { CryptoHolding } from "@/types";
+
+interface CryptoTransactionHistoryModalProps {
+  open: boolean;
+  onClose: () => void;
+  holding: CryptoHolding | null;
+}
+
+export function CryptoTransactionHistoryModal({ open, onClose, holding }: CryptoTransactionHistoryModalProps) {
+  const { t } = useTranslation();
+  const { data: transactions, isLoading } = useCryptoTransactions(holding ? holding.asset_id : null);
+  const deleteTransaction = useDeleteCryptoTransaction();
+
+  if (!holding) return null;
+
+  function handleDelete(transactionId: number) {
+    if (window.confirm(t("crypto.history.confirmDelete"))) {
+      deleteTransaction.mutate(transactionId);
+    }
+  }
+
+  return (
+    <Dialog open={open} onClose={onClose} title={t("crypto.history.title", { name: holding.name })}>
+      {isLoading ? (
+        <p className="py-6 text-center text-sm text-text-muted">{t("common.loading")}</p>
+      ) : !transactions || transactions.length === 0 ? (
+        <p className="py-6 text-center text-sm text-text-muted">{t("crypto.history.empty")}</p>
+      ) : (
+        <ul className="max-h-96 divide-y divide-gridline overflow-y-auto">
+          {transactions.map((tx) => (
+            <li key={tx.id} className="flex items-center gap-3 py-2.5">
+              <span
+                className="shrink-0 rounded px-1.5 py-0.5 text-xs font-medium"
+                style={{
+                  color: tx.type === "buy" ? "var(--success)" : "var(--danger)",
+                  backgroundColor: tx.type === "buy" ? "color-mix(in srgb, var(--success) 12%, transparent)" : "color-mix(in srgb, var(--danger) 12%, transparent)",
+                }}
+              >
+                {tx.type === "buy" ? t("crypto.form.buy") : t("crypto.form.sell")}
+              </span>
+              <span className="min-w-0 flex-1">
+                <span className="block text-sm text-text-primary">
+                  {Number(tx.quantity)} {holding.symbol} · {formatCurrency(tx.price_per_unit)}
+                </span>
+                <span className="block text-xs text-text-muted">
+                  {formatTransactionDate(tx.date, true)}
+                  {tx.note && ` · ${tx.note}`}
+                </span>
+              </span>
+              <button
+                type="button"
+                aria-label={t("common.delete")}
+                onClick={() => handleDelete(tx.id)}
+                className="shrink-0 rounded-md p-1.5 text-text-muted hover:bg-surface-2 hover:text-danger"
+              >
+                <Trash2 size={15} />
+              </button>
+            </li>
+          ))}
+        </ul>
+      )}
+    </Dialog>
+  );
+}
--- a/frontend/src/components/crypto/CryptoTransactionModal.tsx
+++ b/frontend/src/components/crypto/CryptoTransactionModal.tsx
@@ -0,0 +1,138 @@
+import { type FormEvent, useEffect, useState } from "react";
+import { ApiError } from "@/api/client";
+import { Button } from "@/components/ui/Button";
+import { Dialog } from "@/components/ui/Dialog";
+import { Input, Label } from "@/components/ui/Input";
+import { useAddCryptoTransaction } from "@/hooks/useCrypto";
+import { useTranslation } from "@/lib/i18n";
+import { cn } from "@/lib/utils";
+import type { CryptoHolding, CryptoTransactionType } from "@/types";
+
+interface CryptoTransactionModalProps {
+  open: boolean;
+  onClose: () => void;
+  holding: CryptoHolding | null;
+}
+
+/** Buy more of, or sell some of, a coin already being tracked — the "+"
+ * action on the holdings table. Never calls CoinGecko (see
+ * services/crypto_service.py's add_transaction): value is recomputed from
+ * the last cached price. */
+export function CryptoTransactionModal({ open, onClose, holding }: CryptoTransactionModalProps) {
+  const { t } = useTranslation();
+  const addTransaction = useAddCryptoTransaction();
+
+  const [type, setType] = useState<CryptoTransactionType>("buy");
+  const [quantity, setQuantity] = useState("");
+  const [pricePerUnit, setPricePerUnit] = useState("");
+  const [date, setDate] = useState(() => new Date().toISOString().slice(0, 10));
+  const [note, setNote] = useState("");
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    if (!open) return;
+    setType("buy");
+    setQuantity("");
+    setPricePerUnit("");
+    setDate(new Date().toISOString().slice(0, 10));
+    setNote("");
+    setError(null);
+  }, [open, holding]);
+
+  async function handleSubmit(event: FormEvent) {
+    event.preventDefault();
+    if (!holding) return;
+    setError(null);
+    try {
+      await addTransaction.mutateAsync({
+        assetId: holding.asset_id,
+        input: { type, quantity, price_per_unit: pricePerUnit, date, note: note || null },
+      });
+      onClose();
+    } catch (err) {
+      setError(
+        err instanceof ApiError && err.status === 400 ? t("crypto.form.errorSellTooMuch") : t("crypto.form.saveError")
+      );
+    }
+  }
+
+  if (!holding) return null;
+
+  return (
+    <Dialog open={open} onClose={onClose} title={t("crypto.form.tradeTitle", { name: holding.name })}>
+      <form onSubmit={handleSubmit} className="space-y-3">
+        <div className="grid grid-cols-2 gap-2">
+          <button
+            type="button"
+            onClick={() => setType("buy")}
+            className={cn(
+              "rounded-lg border px-3 py-2 text-sm font-medium transition-colors",
+              type === "buy" ? "border-success bg-success/10 text-success" : "border-border text-text-secondary"
+            )}
+          >
+            {t("crypto.form.buy")}
+          </button>
+          <button
+            type="button"
+            onClick={() => setType("sell")}
+            className={cn(
+              "rounded-lg border px-3 py-2 text-sm font-medium transition-colors",
+              type === "sell" ? "border-danger bg-danger/10 text-danger" : "border-border text-text-secondary"
+            )}
+          >
+            {t("crypto.form.sell")}
+          </button>
+        </div>
+
+        <div className="grid grid-cols-2 gap-3">
+          <div>
+            <Label htmlFor="tx-quantity">{t("crypto.form.quantityLabel")}</Label>
+            <Input
+              id="tx-quantity"
+              type="number"
+              step="any"
+              min="0"
+              required
+              autoFocus
+              value={quantity}
+              onChange={(event) => setQuantity(event.target.value)}
+            />
+          </div>
+          <div>
+            <Label htmlFor="tx-price">{t("crypto.form.pricePerUnitLabel")}</Label>
+            <Input
+              id="tx-price"
+              type="number"
+              step="any"
+              min="0"
+              required
+              value={pricePerUnit}
+              onChange={(event) => setPricePerUnit(event.target.value)}
+            />
+          </div>
+        </div>
+
+        <div>
+          <Label htmlFor="tx-date">{t("crypto.form.dateLabel")}</Label>
+          <Input id="tx-date" type="date" required value={date} onChange={(event) => setDate(event.target.value)} />
+        </div>
+
+        <div>
+          <Label htmlFor="tx-note">{t("crypto.form.noteLabel")}</Label>
+          <Input id="tx-note" value={note} onChange={(event) => setNote(event.target.value)} />
+        </div>
+
+        {error && <p className="text-sm text-danger">{error}</p>}
+
+        <div className="flex justify-end gap-2 pt-2">
+          <Button type="button" variant="ghost" onClick={onClose}>
+            {t("common.cancel")}
+          </Button>
+          <Button type="submit" disabled={addTransaction.isPending}>
+            {addTransaction.isPending ? t("common.saving") : t("common.save")}
+          </Button>
+        </div>
+      </form>
+    </Dialog>
+  );
+}
--- a/frontend/src/hooks/useCrypto.ts
+++ b/frontend/src/hooks/useCrypto.ts
@@ -1,20 +1,22 @@
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import {
+  addCryptoTransaction,
  createCryptoHolding,
  deleteCryptoHolding,
+  deleteCryptoTransaction,
  fetchCryptoHoldings,
+  fetchCryptoTransactions,
  refreshCryptoPrices,
-  searchCryptoCoins,
-  updateCryptoHoldingQuantity,
 } from "@/api/crypto";
-import type { CryptoHoldingInput } from "@/types";
+import type { CryptoHoldingCreateInput, CryptoTransactionInput } from "@/types";

 function useInvalidateCrypto() {
  const queryClient = useQueryClient();
  return () => {
    queryClient.invalidateQueries({ queryKey: ["crypto-holdings"] });
+    queryClient.invalidateQueries({ queryKey: ["crypto-transactions"] });
    // A crypto holding is a normal Asset under the hood — Net Worth's own
-    // numbers change the moment one is added/edited/repriced/removed.
+    // numbers change the moment one is added/traded/repriced/removed.
    queryClient.invalidateQueries({ queryKey: ["net-worth-summary"] });
  };
 }
@@ -23,6 +25,14 @@ export function useCryptoHoldings() {
  return useQuery({ queryKey: ["crypto-holdings"], queryFn: fetchCryptoHoldings });
 }

+export function useCryptoTransactions(assetId: number | null) {
+  return useQuery({
+    queryKey: ["crypto-transactions", assetId],
+    queryFn: () => fetchCryptoTransactions(assetId!),
+    enabled: assetId !== null,
+  });
+}
+
 export function useRefreshCryptoPrices() {
  const invalidate = useInvalidateCrypto();
  return useMutation({ mutationFn: refreshCryptoPrices, onSuccess: invalidate });
@@ -31,16 +41,24 @@ export function useRefreshCryptoPrices() {
 export function useCreateCryptoHolding() {
  const invalidate = useInvalidateCrypto();
  return useMutation({
-    mutationFn: (input: CryptoHoldingInput) => createCryptoHolding(input),
+    mutationFn: (input: CryptoHoldingCreateInput) => createCryptoHolding(input),
    onSuccess: invalidate,
  });
 }

-export function useUpdateCryptoHoldingQuantity() {
+export function useAddCryptoTransaction() {
  const invalidate = useInvalidateCrypto();
  return useMutation({
-    mutationFn: ({ assetId, quantity }: { assetId: number; quantity: string }) =>
-      updateCryptoHoldingQuantity(assetId, quantity),
+    mutationFn: ({ assetId, input }: { assetId: number; input: CryptoTransactionInput }) =>
+      addCryptoTransaction(assetId, input),
+    onSuccess: invalidate,
+  });
+}
+
+export function useDeleteCryptoTransaction() {
+  const invalidate = useInvalidateCrypto();
+  return useMutation({
+    mutationFn: (transactionId: number) => deleteCryptoTransaction(transactionId),
    onSuccess: invalidate,
  });
 }
@@ -52,8 +70,3 @@ export function useDeleteCryptoHolding() {
    onSuccess: invalidate,
  });
 }
-
-// Not a useQuery — this drives a search-as-you-type picker inside the "add
-// holding" modal, called imperatively (debounced) rather than kept in sync
-// with a query key.
-export { searchCryptoCoins };
--- a/frontend/src/lib/i18n.ts
+++ b/frontend/src/lib/i18n.ts
@@ -123,9 +123,29 @@ const ru = {
  "crypto.search.empty": "Ничего не найдено.",
  "crypto.search.noApiKey": "Не настроен ключ CoinGecko API — задайте AURUM_COINGECKO_API_KEY в .env (бесплатный ключ на coingecko.com/en/api/pricing).",
  "crypto.form.quantityLabel": "Количество",
+  "crypto.form.pricePerUnitLabel": "Цена за штуку",
+  "crypto.form.dateLabel": "Дата",
+  "crypto.form.noteLabel": "Заметка (необязательно)",
  "crypto.form.addTitle": "Добавить {{name}}",
-  "crypto.form.editTitle": "Изменить количество: {{name}}",
+  "crypto.form.tradeTitle": "Сделка: {{name}}",
+  "crypto.form.tradeButton": "Купить / продать",
+  "crypto.form.buy": "Покупка",
+  "crypto.form.sell": "Продажа",
+  "crypto.form.errorSellTooMuch": "Нельзя продать больше, чем у вас есть.",
  "crypto.form.saveError": "Не удалось сохранить. Проверьте данные и попробуйте снова.",
+  "crypto.table.name": "Название",
+  "crypto.table.price": "Цена",
+  "crypto.table.change1h": "1ч%",
+  "crypto.table.change24h": "24ч%",
+  "crypto.table.change7d": "7д%",
+  "crypto.table.holdings": "Держите",
+  "crypto.table.avgBuyPrice": "Средняя цена покупки",
+  "crypto.table.profitLoss": "Прибыль/убыток",
+  "crypto.table.actions": "Действия",
+  "crypto.history.title": "История сделок: {{name}}",
+  "crypto.history.empty": "Пока нет ни одной сделки.",
+  "crypto.history.confirmDelete": "Удалить эту сделку? Количество и средняя цена будут пересчитаны.",
+  "crypto.history.viewButton": "Смотреть историю",

  "roi.calculator.title": "Калькулятор ROI",
  "roi.calculator.investmentLabel": "Сумма инвестиции",
@@ -551,9 +571,29 @@ const en: Record<keyof typeof ru, string> = {
  "crypto.search.empty": "Nothing found.",
  "crypto.search.noApiKey": "CoinGecko API key not configured — set AURUM_COINGECKO_API_KEY in .env (free key at coingecko.com/en/api/pricing).",
  "crypto.form.quantityLabel": "Quantity",
+  "crypto.form.pricePerUnitLabel": "Price per unit",
+  "crypto.form.dateLabel": "Date",
+  "crypto.form.noteLabel": "Note (optional)",
  "crypto.form.addTitle": "Add {{name}}",
-  "crypto.form.editTitle": "Edit quantity: {{name}}",
+  "crypto.form.tradeTitle": "Trade: {{name}}",
+  "crypto.form.tradeButton": "Buy / sell",
+  "crypto.form.buy": "Buy",
+  "crypto.form.sell": "Sell",
+  "crypto.form.errorSellTooMuch": "You can't sell more than you currently hold.",
  "crypto.form.saveError": "Failed to save. Check the data and try again.",
+  "crypto.table.name": "Name",
+  "crypto.table.price": "Price",
+  "crypto.table.change1h": "1h%",
+  "crypto.table.change24h": "24h%",
+  "crypto.table.change7d": "7d%",
+  "crypto.table.holdings": "Holdings",
+  "crypto.table.avgBuyPrice": "Avg. Buy Price",
+  "crypto.table.profitLoss": "Profit/Loss",
+  "crypto.table.actions": "Actions",
+  "crypto.history.title": "Trade history: {{name}}",
+  "crypto.history.empty": "No trades yet.",
+  "crypto.history.confirmDelete": "Delete this trade? Quantity and average price will be recalculated.",
+  "crypto.history.viewButton": "View history",

  "roi.calculator.title": "ROI Calculator",
  "roi.calculator.investmentLabel": "Investment amount",
--- a/frontend/src/pages/CryptoPage.tsx
+++ b/frontend/src/pages/CryptoPage.tsx
@@ -3,8 +3,9 @@ import { Plus, RefreshCw } from "lucide-react";
 import { Button } from "@/components/ui/Button";
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/Card";
 import { CryptoAddModal } from "@/components/crypto/CryptoAddModal";
-import { CryptoEditModal } from "@/components/crypto/CryptoEditModal";
-import { CryptoHoldingsList } from "@/components/crypto/CryptoHoldingsList";
+import { CryptoHoldingsTable } from "@/components/crypto/CryptoHoldingsTable";
+import { CryptoTransactionHistoryModal } from "@/components/crypto/CryptoTransactionHistoryModal";
+import { CryptoTransactionModal } from "@/components/crypto/CryptoTransactionModal";
 import { useCryptoHoldings, useDeleteCryptoHolding, useRefreshCryptoPrices } from "@/hooks/useCrypto";
 import { formatCurrency, getIntlLocale } from "@/lib/format";
 import { useTranslation } from "@/lib/i18n";
@@ -21,7 +22,8 @@ export function CryptoPage() {
  const deleteHolding = useDeleteCryptoHolding();

  const [addOpen, setAddOpen] = useState(false);
-  const [editingHolding, setEditingHolding] = useState<CryptoHolding | null>(null);
+  const [tradingHolding, setTradingHolding] = useState<CryptoHolding | null>(null);
+  const [historyHolding, setHistoryHolding] = useState<CryptoHolding | null>(null);

  const holdings = data?.holdings ?? [];
  const totalValue = holdings.reduce((sum, holding) => sum + (holding.value !== null ? Number(holding.value) : 0), 0);
@@ -59,20 +61,32 @@ export function CryptoPage() {
                  <p className="text-2xl font-semibold tabular-nums text-text-primary">{formatCurrency(totalValue)}</p>
                </div>
                <p className="text-xs text-text-muted">
-                  {data?.last_synced_at ? t("crypto.lastSynced", { time: formatSyncedAt(data.last_synced_at) }) : t("crypto.neverSynced")}
+                  {data?.last_synced_at
+                    ? t("crypto.lastSynced", { time: formatSyncedAt(data.last_synced_at) })
+                    : t("crypto.neverSynced")}
                </p>
              </div>

              {data?.error_key && <p className="mb-3 text-sm text-danger">{t(`crypto.syncError.${data.error_key}`)}</p>}

-              <CryptoHoldingsList items={holdings} onEdit={setEditingHolding} onDelete={handleDelete} />
+              <CryptoHoldingsTable
+                items={holdings}
+                onTrade={setTradingHolding}
+                onViewHistory={setHistoryHolding}
+                onDelete={handleDelete}
+              />
            </>
          )}
        </CardContent>
      </Card>

      <CryptoAddModal open={addOpen} onClose={() => setAddOpen(false)} />
-      <CryptoEditModal open={editingHolding !== null} onClose={() => setEditingHolding(null)} holding={editingHolding} />
+      <CryptoTransactionModal open={tradingHolding !== null} onClose={() => setTradingHolding(null)} holding={tradingHolding} />
+      <CryptoTransactionHistoryModal
+        open={historyHolding !== null}
+        onClose={() => setHistoryHolding(null)}
+        holding={historyHolding}
+      />
    </div>
  );
 }
--- a/frontend/src/types/index.ts
+++ b/frontend/src/types/index.ts
@@ -374,26 +374,59 @@ export interface FinancialAlert {
  params: Record<string, number>;
 }

+export type CryptoTransactionType = "buy" | "sell";
+
 export interface CryptoHolding {
  asset_id: number;
  coingecko_id: string;
  symbol: string;
  name: string;
  thumb_url: string | null;
+  // Both derived from the buy/sell log (see CryptoTransaction) — never
+  // edited directly.
  quantity: string;
-  // null means "added but never priced yet" (CoinGecko was unreachable at
-  // creation time) — distinct from a real zero value.
+  avg_buy_price: string | null;
+  // Cached from the last successful CoinGecko sync — null means "added but
+  // never priced yet" (CoinGecko was unreachable right at creation),
+  // distinct from a real zero.
+  current_price: string | null;
+  price_change_1h: string | null;
+  price_change_24h: string | null;
+  price_change_7d: string | null;
  value: string | null;
-  unit_price: string | null;
-  as_of_date: string | null;
+  cost_basis: string | null;
+  profit_loss: string | null;
+  profit_loss_percent: number | null;
 }

-export interface CryptoHoldingInput {
+export interface CryptoHoldingCreateInput {
  coingecko_id: string;
  symbol: string;
  name: string;
  thumb_url?: string | null;
+  // A holding always starts with its first buy.
  quantity: string;
+  price_per_unit: string;
+  date: string;
+  note?: string | null;
+}
+
+export interface CryptoTransaction {
+  id: number;
+  asset_id: number;
+  type: CryptoTransactionType;
+  quantity: string;
+  price_per_unit: string;
+  date: string;
+  note: string | null;
+}
+
+export interface CryptoTransactionInput {
+  type: CryptoTransactionType;
+  quantity: string;
+  price_per_unit: string;
+  date: string;
+  note?: string | null;
 }

 export interface CryptoSyncResult {