Transfer cost basis

Trade → Account history → Performance now carries original acquisition lots between account books for an explicit subset of user-confirmed transfers. Confirmation records ownership/classification; Performance derives current lot allocations from retained facts on each calculation. Neither action moves money or submits orders.

Which links apply

A pair qualifies only when all of these checks pass:

• The saved link is active, both current source records exist, and their material fingerprints still match the reviewed versions.
• The observations remain valid completed, positive, same-asset, same-environment movements between different accounts.
• Without an explicit allocation, reported outgoing/incoming quantities must be exactly equal and both fees explicitly zero.
• Reviewed same-asset fee allocations can apply unequal reported amounts or missing fee assertions when the debit, credit and distinct fee charges balance exactly. Conventions are never inferred. Other-currency fees, rebates and split/merged allocations remain unsupported.
• Receipt follows dispatch. Equal/reversed timestamps, a fill at a movement timestamp, or multiple relevant funding records at that account timestamp leave ordering unresolved.
• The connected asset accounts have one unambiguous retained exact market and quote denomination. A base asset also used in another pair, including as a quote, blocks that connected component. No USD/USDT parity or historical conversion is assumed.
• The pair lies strictly after each applicable opening assertion. A previous transfer is not added on top of a user-entered opening balance.
• The source book has no earlier unresolved funding, incomplete fees, estimated notionals, ambiguous ordering, invalid opening assertion or blocked matching. Later unmatched funding on the source does not retroactively block a previously valid dispatch. Cross-market and timestamp ambiguity checks use the retained market history conservatively.

The UI shows Lots carried or Unapplied, with a reason for each reviewed link. An unapplied link keeps its funding/coverage gap; it does not silently create zero-cost inventory or pretend an amount difference is a fee. Other assets on the same account are not affected by an unrelated unapplied link.

Calculation

The same services/portfolio/fifo.py book handles ordinary fills and transfer-aware calculations. A single chronological replay processes each account's fills, outgoing dispatch and incoming receipt. At dispatch, FIFO slices leave the source book; at receipt, those exact slices enter the destination book. There are no disposal proceeds and no realized P&L for the move.

Each slice retains its original acquisition time, origin fill/opening record, originating account, quantity and cost in the exact market's quote. Partial slices divide cost proportionally with Decimal precision 50. Transfer receipt dates do not reset acquisition age: older transferred units precede newer local purchases. A subsequent eligible transfer carries those same origins through intermediate accounts or back to the original account.

Known zero cost remains known zero. Unknown-cost opening units retain their unknown cost and user-provided date. If a dispatch exceeds retained source inventory, the shortfall is explicit unknown-cost inventory with an unknown acquisition date. For provisional inspection, undated units precede dated lots; final net/marks remain unavailable. Distinct origins sharing an acquisition timestamp also flag ordering ambiguity.

Quote/base trading fees and rebates retain the ordinary FIFO rules. Third-currency fees are not converted. Nonzero same-asset transfer fees require an explicit reviewed allocation. Their inventory cost stays separate from received lots and trading P&L; final net results remain provisional without historical fee valuation.

Dependency and scope rules

Selecting a receiving account first loads and replays its connected donor and intermediate account history. Only then are output account/market/environment filters applied. Otherwise a destination could incorrectly show zero acquisition cost simply because its donor was hidden.

The report includes dependency_fill_count and dependency_account_count; its fill_count describes the displayed rows. Receiving-only accounts can appear with zero local fills and transferred inventory. Disconnected/inactive accounts retain their historical facts and may supply donor lots. Current marks still require an active destination, a matching native balance, known open cost and complete applicable coverage.

Reads use one SQLite snapshot for fills, opening assertions, funding records and link versions. Derived lots are not persisted into source tables. Changing a source fill, re-reviewing a changed funding record, removing/restoring a link or editing opening inventory changes the next replay. A missing/corrected reviewed record remains a gap even if the source row itself disappeared.

Budgets reject rather than truncate:

Input	Limit and scope
Fills	20,000 including dependency accounts, after exact-market/environment selection
Current links	2,000 after asset/environment selection, checked before account-component filtering
Funding observations	20,000 across dependency accounts and the selected asset/environment, including relevant base-currency fees
Link evidence	First 50 report links and first 50 related links per market; all budgeted links still calculate
Lot evidence	First 100 carried slices per link; lot_count discloses the full number

Filtered reports never import another environment's lots. If retained fills for the same account/market mix environments, an unfiltered calculation rejects the selection and asks for an environment filter rather than combining amounts.

Performance and coverage

transfer_summary reports applied/unapplied counts. transfer_evidence contains status/reason, source/destination IDs and labels, dispatch/receipt times, known/unknown quantities, carried cost and bounded original lot slices. Each market includes transfer_in_count, transfer_out_count, funding_event_count and unresolved_funding_count.

Applied pairs clear their two funding gaps. Nonzero transfer fees still suppress final net/marks because historical fee valuation is missing. Other non-failed/non-cancelled observations continue to suppress final net/marks. Without a valid opening assertion, deposits before the first retained fill still count as missing coverage. Observations before an explicit opening boundary are covered by that assertion and not reapplied.

Unknown-cost sales stay excluded from matched P&L. A matching current balance is only an inventory check. This feature does not establish complete provider history, external cash flows, funding-adjusted account returns, historical currency conversions or tax treatment.

Export summary includes applied incoming/outgoing transfer counts and unresolved funding observations alongside the existing P&L/coverage columns. Inspect the on-screen evidence and original ledgers for individual lot records.

Example and Accountant

Transfer example uses the same replay without a database or exchange client. A long-term wallet buys 0.2 BTC at 40,000 USDT; a trading wallet later buys 0.1 BTC at 50,000. A zero-fee 0.1 BTC transfer moves the older lot to the trading wallet. Selling 0.15 BTC at 60,000, with a 9 USDT trading fee, matches 6,500 USDT of cost and 8,991 USDT of proceeds: 2,491 USDT matched realized P&L. Remaining known cost is 6,500 USDT across both wallets. This fixture does not create accounts, fills, funding rows, links or orders.

Select With a transfer fee to inspect the fee-aware variant, or use GET /api/v1/account-ledger/performance/example?transfers=true&fees=true. See fee allocation and its example.

Use GET /api/v1/account-ledger/performance/example?transfers=true for the original zero-fee variant. The existing example endpoint without that flag retains the four-fill/opening-inventory fixture.

The in-page Accountant reads the same calculation through ProtoLink. performance_view, performance_example and performance_transfer_example preserve the page context. Its fixed read-only evidence tool cannot alter filters, edit lots/links or fetch private balances. Evidence limits are explicit: 20 market groups, ten recent disposals per group, six report links, three links per market and five slices per link. Those are response caps, not calculation truncation.

Verification and remaining work

tests/test_transfer_basis.py exercises cost/quantity conservation, partial slices, source fees, original-age FIFO, chains/round trips, unknown/zero basis, source corrections, missing facts, removal/restoration, dependency filters, environment/quote separation, opening overlap, time ambiguity, earlier funding, read budgets, opt-in balance marks, fixture isolation and ProtoLink evidence.

Remaining work includes historical transfer-fee valuation, other fee currencies/rebates, split/merged movements, cross-market acquisition basis, historical fee/flow conversion, reviewed external-funding classification and cash-flow-adjusted account returns. A user-confirmed link is not independent evidence of settlement or ownership.