Gran Turismo Association

The Gran Turismo Association, frequently abbreviated, is presumably the sanctioning body for all races and events in the Gran Turismo series.

About
Not much is known about GT Association, aside from the fact that it probably sanctions all of the races in each game, and that it may be based off the real-life GT-Association that sanctions the Autobacs Super GT Series. The organization's main logo can be seen, among other places, in the intro movie for Gran Turismo 4, on the side of the Ford GT LM Spec II, on Gran Turismo 5's "My Home" screen (the one the player clicks to go into GT Life mode), and during loading screens for Gran Turismo 6. An alternate logo can be found on the start/finish gantry on various tracks, such as Tokyo Route 246, where it has been since Gran Turismo 3.