Will Adelson keep backing Gingrich's run?

The super PAC supporting Newt Gingrich received another large installment in February from the Las Vegas casino billionaire Sheldon Adelson. But it was not the $10 million that a source close to Adelson said the magnate planned to give. Instead, Adelson and his wife, Dr. Miriam Adelson, gave the Winning Our Future super PAC a total of $5 million in February.

Thrown in for good measure was another half million from an Adelson daughter, Shelley Maye Adelson.

This leaves the Adelson family with donations totaling $16.5 million to Winning Our Future, or 87 percent of the total $18.8 million the super PAC raised so far. By the end of February, Winning Our Future had about $2.2 million remaining, according to records filed at the Federal Election Commission.

What will Adelson do next? It's unclear. The mogul has long said he would support the ultimate nominee, no matter who that was. It's not yet known if he has chipped in any more money to the super PAC supporting Gingrich since February 17th. Calls to Adelson's Las Vegas Sands Hotel were not returned.

Rick Tyler, who runs Winning Our Future, declined to comment about money in the bank or any future ad buys. He told CBS News, "The race is dynamic and we'll be in it as long as Newt's in it."

Tyler said he has not heard anything negative from Adelson's camp and says, "It's been reported in the past that there was a 'last check' and that turned out not to be true."

According to FEC records, the last ad buy for Winning Our Future was in Alabama and Mississippi for $120,000 on March 11th.

Funding for both Winning Our Future and Gingrich's campaign was down in February.

The super PAC went from $11 million raised in January to $5.7 million in February. Gingrich's campaign went from raising $5.6 million in January to just $2.6 million a month later.

Adelson isn't the only super PAC billionaire who might be waning in his support.

Silicon Valley venture capitalist Peter Thiel, who gave $2.6 million to the super PAC supporting Ron Paul, Endorse Liberty, didn't give any money to the super PAC in February. That left the group with just $280,000, compared to $2.3 million in the month before. Paul's spokesperson Jim O'Neil told CBS News that Thiel still supports Ron Paul for president.