Robert Holmes Tuttle, a major fundraiser for President Bush who runs Tuttle-Click Automotive Group, one of California’s biggest car dealerships, is being vetted by the White House to determine if he is suitable to fill the post, which has been vacant for seven months.
The US ambassadorship has been vacant since July.
Tuttle, who lives in Beverly Hills, has been a prominent California Republican for 30 years and raised at least $100,000 (£52,095) for Bush’s re-election. He also gave $100,000 towards Bush’s inauguration celebrations in January.
The White House has yet to approach London about the appointment, as the vetting process is believed to be in the very early stages.
Tuttle's company has 10 new- and used-car dealerships in Orange County, California, and in Tucson, Arizona.