"participation interests" refers to the level of involvement or engagement that someone has in something. It represents how actively or enthusiastically someone takes part in a particular activity or event. Full definition
The investment bank then sells participation interests («certificates») in the trust. (alephblog.com)
Floating Rate Funds invest primarily in participation interests in collateralized senior corporate loans that have floating or variable rates. (nylinvestments.com)
Metro Diner also allows significant ability to realize the value of the partner's participation interest after five years. (foodnewsfeed.com)