Lot-Based vs Spread-Based Commission

Lot-based and spread-based commissions are the two dominant models for compensating introducing brokers in Forex. Lot-based pays a fixed dollar amount for every standard lot a referred trader executes -- for example, $5 per lot. Spread-based pays a share of the spread markup the broker earns on each trade, tying the IB's earnings directly to the broker's per-trade revenue.

The practical difference matters most when spreads vary across instruments. On a major pair like EUR/USD with tight spreads, a fixed per-lot payout may exceed what the broker actually earns on the trade. On exotic pairs with wider spreads, the same per-lot rate may undervalue the IB's contribution. Spread-based models adjust automatically because the payout is a function of the markup itself.

For IBs, lot-based is easier to understand and forecast. For brokers, spread-based offers tighter alignment between partner costs and revenue. Many brokers offer both models and let IBs choose, or assign the model based on the IB's tier, volume, or the instruments their traders focus on. The right commission engine needs to support both models simultaneously and calculate them accurately at scale.