Rubio, believed to have presidential aspirations in 2016, had another fundraiser scheduled for Wednesday, the newspaper said. This one was to be held at a Washington barbecue restaurant for lobbyists willing to pony up at least $500.
"If you want to be president, you hire political consultants, fundraisers. People who work on your brand. That's pretty clear what he's done," Sheila Krumholz, executive director of the Center for Responsive Politics, said.
Rubio has raised $5 million this year, much of it through his political action committee, Reclaim America. The Center for Responsive Politics said only 4 percent of the money raised for the PAC was passed on to other political candidates in 2011 and 2012.
While polls -- and at least one heckling incident -- suggest Rubio's immigration stance has turned off some of the Republican base, it also appears to be bringing in money from business interests, the Times said.
Terry Sullivan of Reclaim America says the PAC is spending more this year, including $100,000 to help Sen. Kelly Ayotte, R-N.H., who is under attack from gun control advocates.
"This year he's redoubled his efforts to help conservative candidates and causes," Sullivan said. "You'll continue to see him use the Reclaim America PAC to travel the country campaigning with and raising money for other conservative candidates."
Many of Rubio's efforts this year appear targeted towards 2016, the Times said. New Hampshire holds the first presidential primary, and Rubio also made a trip this week to Virginia, a key swing state, to support Ken Cuccinelli, the Republican candidate for governor.