For every program line, regardless of which mechanism plug-in the program line uses, you will have the option of ticking the **Inverse earnings** box.

For example, suppose a program line has a fixed percentage rate of 5% and a total value across the matching transaction lines of £100,000 and the **Inverse earnings **box is **not** ticked.

For this program line, calculating the earnings will involve both of the following, regardless of whether the inverse earnings box is ticked:

- Multiplying the percentage rate (5%) by the transaction value for the program line (£100,000) to derive a program line result for earnings (£5,000).
- Multiplying the percentage rate (5%) by the transaction value for the transaction to derive an earnings result for each of the matching transactions.

Now suppose the **Inverse earnings** box **is** ticked. Trading Programs will include an additional step in the earnings calculation that involves multiplying each of the following by -1:

- The program line result for earnings (to give an earnings result of -£5,000).
- The earnings result for each of the matching transactions.

The step of multiplying by -1 is always applied as the final step after the program line and transaction earnings have been calculated. Except for this final step, the earnings calculations for a program line where the **Inverse earnings** box is ticked are identical to those that would be performed for the same program line if the **Inverse earnings** box was not ticked.

As the inverse earnings step always involves multiplying the calculated earnings by -1, ticking the **Inverse earnings** box will:

- Generate negative earnings where a positive result would have been returned for a program line where the inverse earnings box is not ticked.
- Generate positive earnings where a negative result would have been returned for a program line where the inverse earnings box is not ticked.