JAY Z and Kevin Durant's public appearances together might be limited thus far, but Shawn Carter on Friday once again proved who's pulling the business strings behind the scenes.

According to Businessweek, JAY Z (or Mr. Z, as the publication calls him) has intervened in Under Armour's battle for the Oklahoma City Thunder star, giving current sponsor Nike until Wednesday (Aug. 27) to match the sports apparel company's offer, which is worth between $265 million and $285 million for 10 years.

The Under Armour battle has proved to be the latest instance of JAY Z flexing his business muscle on Durant's behalf. It's also made some Thunder fans nervous as they become aware of the rapper's negotiating power come 2016, when the NBA MVP's contract with OKC expires.

Since signing with Roc Nation Sports last year, Durant also parted ways with Gatorade, signing with zero calorie drink Sparkling Ice last month.

Durant has previously assured fans Jay's representation "has nothing to do with if I'm going to leave OKC or none of that," he told a local newspaper last year. "He knows his lane with me. Their team knows their lane with me. And they're letting me handle the basketball part. I would tell fans not to worry about that at all."