The NHL's Board of Governors gave unanimous approval to the deal Wednesday. Vinik agreed to buy the team, the company that operates the St. Pete Times Forum and more than five acres of land adjacent to the downtown arena on Feb. 4.
Financial terms were not disclosed. The Boston financier reportedly paid about $110 million cash -- substantially less than the $206 million a group led by Oren Koules and Len Barrie paid for the franchise in June 2008.
Vinik takes controls of a franchise that's struggled on the ice and at the box office since winning the Stanley Cup in 2004.
"The Lightning is a great franchise in a terrific community," Vinik said in a statement released by the team. "We thank Oren Koules and his partners for beginning the turnaround of the Lightning hockey club. Our goal now is to build a world-class organization, on and off the ice."
Prior to being purchased by Koules and Barrie, the Lightning had been owned since 1999 by Palace Sports & Entertainment, a group led by the late Detroit Pistons owner Bill Davidson that helped transform Tampa Bay from a perennial last-place team into a Stanley Cup champion.
Vinik, 50, managed Fidelity's Magellan Fund before founding Vinik Asset Management.