Caroline Wozniacki studied Dwyane Wade's sock range, while Garbine Muguruza is currently investigating the business interests of Roger Federer and LeBron James.
Johanna Konta, meanwhile, has been reading up on the careers of Chip and Joanna Gaines - the home makeover reality TV couple from Texas.
The three WTA stars are all past or present students of a three-month course at Harvard University, which gives athletes the chance to develop business skills by working alongside current MBA students.
The programme, now in its fifth year, has also been completed by two-time Grand Slam champion Victoria Azarenka, former NBA player Chris Bosh, and Olympic and World Cup-winning footballer Heather O'Reilly.