Execution Fees Need a Currency and a Valuation Time
By DX Research Group · · Execution mechanics
A fee ledger should preserve native amounts before conversion. A two-rate example separates execution cost from later changes in the fee asset’s price.
A fee amount without currency cannot establish economic cost. We would preserve the venue-native fee and its token before expressing it in a reporting currency. Hyperliquid fill examples include feeToken; the documentation says total fee includes any optional builderFee. That field relationship matters because adding both as separate costs would double-count the builder component.
Store the fee before converting it
Illustrative generic multi-currency case: an execution charges 0.02 units of fee token X. A time-valid conversion rate of $50 per X values the fee at $1.00. Tomorrow’s $60 rate would value the same token quantity at $1.20. The additional $0.20 is a valuation difference produced by the changed conversion timestamp; the original fee debit stays fixed. Token X is a fictional fee asset in this hypothetical currency example.
Keep native and reporting ledgers joined
Store native amount, token identity, fill time, reporting currency, conversion source and conversion timestamp. Use an explicitly documented price policy when a direct reporting pair is absent. A missing conversion should leave native cost visible and reporting cost unresolved. Test an illustrative total fee of $1.00 containing a $0.25 builder component: expense remains $1.00, with $0.25 tagged as its component. Then test a negative native fee as a signed ledger value rather than clipping it to zero or treating it as missing.
A conversion audit
The conversion policy should be identical across compared agent runs. Otherwise a change in the reporting price source can appear as a change in execution skill. Store enough source evidence to revalue the native fee later, while keeping the original valuation visible. A retrospective common-currency restatement changes the reporting valuation while preserving the original account debit.
Our execution and reconciliation framework provides the broader mandate-to-outcome trace. The state and memory contract explains how the verified result should enter the next decision. These notes narrow those published methods to one execution boundary; the worked amounts above are illustrative and the test is a proposed local fixture. The source inspected for the venue-specific statements is the official Hyperliquid user fill documentation.
If the conversion source later corrects a price, preserve the original report and tag the revised valuation. The native debit remains the stable economic receipt even when the reporting-currency interpretation changes during a subsequent audit.