The massive effort by the super PAC -- which has been funded by seven-figure donations from hedge fund executives Paul Singer and Kenneth Griffin, among other wealthy patrons -- comes at a do-or-die time for Rubio, who lags behind Donald Trump and Ted Cruz in the delegate count. He has pledged he will win Florida, but his campaign has yet to spend any money on air time in the state yet, according to media tracking information obtained by The Washington Post. It did make small buys in Hawaii and Idaho, which hold their primary contests Tuesday.
Campaign officials said they had always planned on putting their resources into get-out-the-vote operations in Florida, leaving the airwaves to their independent allies.
Conservative Solutions PAC and its sister nonprofit, which ran ads supporting Rubio last year, have been pivotal financial backers of the senator, who had raised just under $38 million for his campaign committee by the end of January.
Heading into February, Rubio had just $5.1 million cash on hand. He has not yet said what he raised in February. That information must be reported to the FEC by March 20.
But his allied super PAC appears to have ample resources. In all, the group has reported spending more than $53 million, meaning it brought in $20 million since Jan. 31.
That makes Conservative Solutions PAC the second-biggest spending super PAC of the cycle after Right to Rise USA, the super PAC that raced through $101 million to bolster former Florida governor Jeb Bush before he dropped out.
John Muyskens in Washington and Philip Rucker in Miami contributed to this report.