Or at least, that’s what their contributions show. According to The News Tribune (a Tacoma newspaper):
Obama and Clinton split the support of Microsoft co-founders Bill Gates and Paul Allen. Gates gave $2,300 to the Obama campaign, while Allen gave $4,600 to Clinton.
If you are wondering why billionaires such as Gates and Allen would give the amounts they did, you need to know that current campaign finance law prohibits donations above $2,300 to a candidate for any given election. Allen’s $4,600 is actually two donations of the maximum allowed: one for Clinton’s campaign in the primary election and one for her campaign in the general election.