The Prototype Technology Group team that masterminded BMW's sportscar successes with the M3 in North America in the 1990s and 2000s is closing its doors.
Tom Milner's Virginia-based PTG squad was appointed by BMW North America to mastermind its entry into the IMSA series with the E36-shape M3 in 1995.
The partnership yielded titles in IMSA, the United States Road Racing Club championship, the American Le Mans Series and Grand-Am across 11 seasons and two generations of M3.
Milner said: "I have now sold everything except the building, including the trucks and all the equipment. I'm certainly not going to run my own team again, but I wouldn't rule out an involvement helping someone else."
The German, whose son Tommy Milner is a factory Chevrolet driver in the ALMS, explained that there were a number of reasons behind his decision to close the team.
"There are lots of factors involved and one of them is that sportscar racing in North America is changing," he said. "I'm not saying it is for better or for worse, but there is definitely less money around.
"The other thing is that I am now 70 and have been doing this for 45 years. Maybe it is the right time to stop."
PTG's relationship with BMW came to an end at the conclusion of its 2006 ALMS campaign, after which Milner's team ran works Panoz Esperante in the GT2 class of the series in 2007-09.
It subsequently built and briefly raced the one-off Panoz Abruzzi GT2 car and last year ran the Oryx Racing Audi R8 GRAND-AM in two races, including the Daytona 24 Hours.
Milner, who emigrated to the US with his parents when he was 16, formed Bill Scott Racing with the late Bill Scott in 1969, competing in a variety of single-seater series as well as in sportscars.
He then set up on his own in 1988 as Tom Milner Racing, running Ford Probe Mustang, Spice and Intrepid GTP prototype machinery in IMSA and, briefly, a Chevrolet in the NASCAR Busch Series before changing the team's name to PTG ahead of the BMW programme.
Did you know...
... Tom Milner arrived on the PTG name by reversing the letters of IMSA's GTP class.