New in 2024 shareholder called Mr. X. S corp.

These payments to Mr. X sound like guaranteed payments.  But S Corps don't have GP.  

What is the tax treatment of these payments?

Excerpt from stock purchase agreement between X and Y:  Transfer of Projects. At the time of share transfer, Mr. X will transfer the following three projects to Company Y, deleted. In addition to Mr. X’s normal compensation, Company Y will pay Mr. X 10% of project receipts from these three projects until the amount of these special payments reaches $37,500. These special payments will be made approximately semi-annually or on a different schedule as agreed by the shareholders.