Signage is seen at the Blackstone Group headquarters in New York City, U.S.Jeenah Moon/ReutersPrivate equity is sharing profits with employees to boost returns.Earlier this year, Blackstone rolled out an ownership plan for employees of HVAC company Copeland.Here's how it works, who benefits, and why we can expect to see more such plans.The private-equity industry is famous for taking control of companies to maximize returns for investors.