What is Gains ?
Gains meaning Increases in the institution’s net assets from peripheral or incidental transactions. This is in contrast to revenues, which occur from the institution’s ongoing major or central operations. Whether a transaction generates revenue or a gain depends on the relationship of the transaction to the institution’s activities. For example, the sale of computers by a college store might be part of ongoing central activities, while the sale of surplus computers from administrative offices might be considered otherwise.
reference: IPEDS Data Collectrion System – Glossary