What do you call the reward money for the profit you made?

Solution 1:

I've read the question and all of the comments. What you are talking about is not reward money, because that phrase is reserved for people who have done something like return lost or stolen property.

In the question and the comments, what's being described is an agent who trades stock on behalf of somebody else. When they make a profit, the agent makes a percentage of those profits.

In both stock trading and sales, the agent receives a commission:

[Merriam-Webster]
6 a fee paid to an agent or employee for transacting a piece of business or performing a service
especially : a percentage of the money received from a total paid to the agent responsible for the business
// He gets a commission for each car he sells.

Sometimes a commission is a fixed amount, but it's also often percentage based. People who get a percentage of what they make have more incentive to make more.

Solution 2:

Another word to consider is actually an acronym that turned into a word. Spiff which stands for Sales Program Incentive Funds. It is an incentive program that companies and businesses use to drive sales. When merchandise is not selling well, or if inventory items need to be sold or cleared, the company runs a campaign.

This would be more of a special reward paid on top of your normal commissions.