The real estate developer and owner of the Tampa Bay Lightning hockey team revealed billions of dollars of trading in the stock market -- only now it’s being done through a family philanthropy that is scoring the same kind of robust returns his hedge fund once did.

Vinik’s active trading is unusual in the staid world of charitable foundations. Using just a sliver of its capital, the Vinik Family Foundation traded $1.9 billion of public securities during 2015, realizing $6.7 million in gains, according to the latest available federal tax documents requested from the IRS by Bloomberg and posted last month. The profits were enough to cover most of the foundation’s donations that year and enabled it to beat the broad stock market.

“They are buying a whole bunch during the year and they are turning it over a bunch,” Brian McAllister, an associate professor of accounting at the University of Colorado’s graduate school of business administration, said after reviewing the tax documents. “It could be one indication of high-velocity trading.”

After announcing in May 2013 that he would return outside capital, Vinik converted his fund company into a family office and began focusing on projects tied to his home base in Tampa, Florida, ranging from gifts to local charities to a $3 billion development project in partnership with Bill Gates’sCascade Investment. But Vinik told the Boston Globe two years ago that giving up his money-management career “was a very hard decision,” adding,“I really do miss the markets.” […]