Implementation guide · IB Commission Operations
Per-Lot Commission: Eligible Volume and Rebates
Calculate a forex rebate from eligible closed lots, partial closes and versioned rates. Work through exclusions and reconcile the partner amount.
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Published by FxTrusts, a supplier of brokerage and prop firm technology. Prepared with AI-assisted research and drafting; reviewed against the cited public sources. Examples are illustrative. Product links describe our services.
Quick answer
A per-lot rebate multiplies eligible trading volume by an agreed amount per lot. The agreement must define the lot unit, eligible instruments, qualifying event and rate currency. A position size shown on a platform is not automatically the volume that earns a partner commission.
Define the unit before applying the rate
A lot is a contract quantity, not a universal cash value. Check the symbol specification and map platform volume into the unit named in the partner agreement. Forex, metals and other CFDs can have different contract sizes. If one system sends base-currency units and another expects lots, retain the conversion used for that symbol. MQL5 documents contract and volume properties; IBKR illustrates that fee units and currency can depend on the product. Neither source establishes the terms of your rebate program.
Sources for this section
- MQL5: symbol properties and contract volumewww.mql5.com
- IBKR Broker Portal: commission markups and trade unitswww.ibkrguides.com
Choose the event that earns the rebate
The calculation might use opened volume, closed volume, each executed side or completed round turns. Those models produce different totals. For a closed-volume model, a partial close contributes only its closed quantity. Do not add the original opening quantity again unless the contract explicitly pays both sides. Link each eligible quantity to its execution identifier so a repeated import cannot earn a second rebate. Keep a rejected or excluded event with its reason rather than hiding it from the reconciliation.
Apply the rate that was effective for that activity
Store the agreement version, rate, eligible symbol group and effective timestamp alongside the result. A rate edited today should not silently rewrite a previous statement. Decide how trades spanning a rate change are handled before calculating them: the relevant event may be the opening or closing execution. A correction should identify which historical rule was wrong. Keep original units and calculated amounts separate from display rounding so the calculation can be reproduced later.
Reconcile quantity and money independently
First total the eligible volume and compare it with the trading-event source. Then multiply each rate group and reconcile the money. A correct cash total can conceal offsetting quantity mistakes. Investigate an unexpected negative commission, an unknown symbol mapping or a deal assigned to two partners before approving payment. A sample of one ordinary trade is insufficient: include partial closes, excluded symbols and a replayed execution in the acceptance evidence.
Worked closed-volume example
Assume a fictional agreement pays USD 4 per eligible closed forex lot, once on closing. Metals and still-open volume do not qualify. A 1.5-lot position closes in two pieces of 0.4 and 0.6 lots during this statement period; its remaining 0.5 lots stay open. Another position closes 1.2 lots. The table separates eligible volume from positions that merely exist.
| Activity | Eligible closed lots | Rebate |
|---|---|---|
| First partial close | 0.4 | USD 1.60 |
| Second partial close | 0.6 | USD 2.40 |
| Other full close | 1.2 | USD 4.80 |
| Open remainder and 0.8 metal lots | 0 | USD 0.00 |
| Total | 2.2 | USD 8.80 |
Implementation checklist
- Record the contract unit, earning event and rate currency.
- Match each eligible execution to one partner and one calculation record.
- Test partial closes, exclusions and duplicate imports.
- Retain the effective agreement version with the statement.
Sources
These documents support the reference. Check the original publication for current requirements and the limits of its scope.
- MQL5: symbol properties and contract volumewww.mql5.com
- IBKR Broker Portal: commission markups and trade unitswww.ibkrguides.com
Continue with the broader guides
Connect this reference to platform selection and the wider operating workflow.