Two ways a rebate is calculated, and why it changes which account is best
Most rebate pages give you one number per account type and let you assume it is a fixed property of that account. It is not. Rebates are calculated in two structurally different ways, and which one applies to you decides whether your rebate is stable or moves with the market.
Two models, not one
A share of the spread. The broker takes a percentage of the spread it collected on your trade and passes it to the partner. Because the spread moves, the rebate moves with it. A wider spread means a larger rebate on that trade.
A fixed amount per lot. The broker pays a flat figure for every lot traded, regardless of what the spread was at that moment. Wide spread or tight, the rebate is the same.
Both are normal. Neither is a trick. But they behave so differently that comparing a percentage account against a fixed account using a single headline number will mislead you.
Why this matters more on some instruments than others
A spread-share account is most generous exactly when trading is most expensive, because both numbers come from the same spread. On a wide instrument, or during a session when spreads stretch, the share grows.
That sounds like an advantage, and sometimes it is. But read it the other way round: the rebate grew because your cost grew. A larger rebate on a wider spread is not the same as a cheaper trade.
A fixed account is the opposite. The rebate is boring and predictable, and when spreads widen you simply pay more with no compensation. When spreads are tight, the fixed amount can be worth more than a percentage would have been.
| Spread share | Fixed per lot | |
|---|---|---|
| Rebate when spread widens | Grows | Unchanged |
| Rebate when spread tightens | Shrinks | Unchanged |
| Easy to predict | No | Yes |
| Moves with the instrument | Yes | No |
The comparison that actually answers the question
Because the two models respond differently to the same market, the only comparison worth making is the one that includes everything:
Spread paid, plus commission paid, minus rebate received, on the instrument you actually trade.
Any one of those three on its own can point at the wrong account. A tight raw spread with commission can lose to a wider standard spread once the rebate lands. A large rebate can belong to an account that was expensive to begin with.
Our [rate table for each broker](/brokers) shows which model applies to each account type, and the [trading calculator](/tools/calculator) puts all three components together for the volume and pair you choose.
The figures move when a broker changes terms or when spreads shift. Read them from the live table rather than from any article, including this one.
The short version
If your account pays a share of the spread, your rebate is a moving number tied to your cost. If it pays a fixed amount per lot, your rebate is a constant and your cost is the thing that moves.
Knowing which one you are on is the first step to comparing anything.
Next
- [How to compare two account types without fooling yourself](/bai-viet/compare-account-types-properly)
- [Who is the IB in forex, and where does their money come from](/bai-viet/who-is-the-ib-in-forex)