Sometimes, Henry Kravis and George Roberts like to finish last.

As the founders of buyout-firm KKR gear up to raise their next fund, key investors like California Public Employees' Retirement System, known as Calpers, will likely continue their longstanding push for better terms. But, while KKR has reduced fees over the years and generally structured funds to be more investor-friendly, it has clung to a proactive most firms have stopped: It still collects a percentage of all profits earned by its funds.