Partial exits: allocate fees and funding without double counting

Separate attribution from the exchange cash ledger

An exchange debits a fee or funding payment at an actual time. An analytical journal can allocate that cost across position units to compare exit tranches. Allocation does not move the cash payment in time or change account equity. Keep the original debit and the attribution ledger as separate views of the same cost.

This lesson uses proportional allocation by original quantity for costs incurred while the full position was open. A fee of 1 USDT on ten units allocates 0.10 per unit. If funding is charged after some units have closed, allocate it only to the position exposed at that settlement under the venue’s actual rules, not automatically to all original units.

Reconcile the remaining cost balance

For each partial exit, attribute its share of eligible entry and holding costs, then add the actual exit fee. Carry the unallocated balance with the remaining units. The sum of attributed and remaining costs must equal the original cost ledger at every step.

If fees are charged in another asset, retain the quantity and conversion convention. Rounding should not create or erase costs: assign any final rounding residual explicitly. Adding to a position, inverse payoffs and changes in funding exposure require a richer lot ledger than the one-entry linear example below.

Worked example: two exits reconcile to 5.99 USDT net

Buy ten hypothetical linear units at 100. The entry fee is 1 USDT and a funding charge of 2 occurs while all ten units remain open. Four units exit at 110 with a 0.44 exit fee. Allocate 0.40 of entry fee and 0.80 of funding to them: their attributed net P&L is 40 − 0.40 − 0.80 − 0.44 = 38.36.

The remaining six units later exit at 95, with no further funding and a 0.57 exit fee. Their gross P&L is −30; remaining entry and funding costs are 0.60 and 1.20. Attributed net is −32.37. Together the tranches earn 5.99, matching gross 10 minus entry fee 1, exit fees 1.01 and funding 2. All rates and fills are constructed assumptions.

Attributed realized P&L is not the cash balance

After the first exit, the actual booked cash change from the listed events is 40 − 1 − 2 − 0.44 = 36.56 USDT, excluding unrealized P&L. The first tranche’s attributed net is 38.36 because 1.80 of already paid costs remains analytically assigned to the open six units. Calling 38.36 the account’s cash gain would confuse two valid but different ledgers.