Sheldon Adelson
© Agence France-Presse/Getty Images/Aaron TamSheldon Adelson, billionaire #32 to give to Romney-backing super PAC.
Casino mogul Sheldon Adelson has reportedly donated $10 million to a super PAC supporting Mitt Romney, as he hinted he would after a recent Las Vegas meeting with the GOP candidate.

Adelson's $10 million check is by far the biggest gift to date to Restore Our Future, a group that's attracted five new billionaire donors in as many weeks.

As my colleague Steve Bertoni pointed out, having spoken at length to Adelson for a Forbes cover story, $10 million may just be the start of the Las Vegas Sands chief's generosity. He may well give $100 million, as he'd planned to donate to Newt Gingrich's now-defunct campaign.

Adelson is just the latest billionaire to jump on the Mitt Romney bandwagon. With his gift, the tally of America's richest people donating to Mitt Romney-backing super PAC Restore Our Future is 32 - or, 8% of the Forbes 400.

Look for that number to swell in the coming months as wealthy donors who'd been firmly on Team Newt Gingrich or Rick Perry, for instance, concede and write checks to Romney versus the alternative - a second Obama term.

Here are the 31 billionaires who've joined Sheldon Adelson in backing Restore Our Future:
  • Vulture investor Wilbur Ross, who donated $100,000 in May.
  • Oil and gas pioneer Harold Hamm, who added $985,000 to the pro-Romney PAC's cash pile.
  • Retail king Leslie Wexner of The Limited clothing chain, who wrote a check for $250,000.
  • Gristedes supermarkets head John Catsimatidis, who gave $50,000 via his United Refining oil company.
  • Hedge fund king Louis Bacon, who's handed over $500,000 so far.
  • Jim Davis, who made his fortune with New Balance sneakers and has donated $1 million.
  • Citadel hedge fund chief Ken Griffin has handed over $2.85 million since December.
  • Greenwich-based hedge funder Paul Tudor-Jones II kicked in $200,000.
  • New York investor Thomas Kaplan wrote a check for $100,000.
  • While neither Charles nor David Koch has given publicly to a Romney-backing super PAC this cycle, David's twin brother Bill, "the other Koch", has given $2 million total, both personally and via his Oxbow Carbon company.
  • New York hedge funder Bruce Kovner opened his wallet to the tune of $500,000.
  • Leveraged buyout pioneer Henry Kravis followed suit with a $100,000 gift.
  • Hotel heirs Bill and Richard Marriott have given $1 million each to the cause.