Billionaire Larry Ellison, a generous contributor to the presidential aspirations of Republican U.S. Senator Marco Rubio, doubled down recently on his support for the White House hopeful to the tune of $1 million.

Oracle's executive chairman contributed the sum in January to Conservative Solutions PAC, a political action committee backing the Florida freshman senator's White House bid, federal campaign data showed. Although the PAC had dozens of other large contributors, Ellison was by far the most generous of those listed.

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Overall, Ellison has donated at least $4 million to Rubio's campaign, as it seeks to make his case to GOP primary voters. For the period ending January, Conservative Solutions PAC had raised $2.5 million, FEC data showed.

The news was first reported on Saturday by Politico.

