The wealthy donors who have built a powerful shadow Republican Party of outside groups are rapidly cleaving into two mutually hostile and deep-pocketed factions, complicating efforts to deny the party’s nomination to Donald J. Trump, reports filed with the Federal Election Commission on Sunday showed.

Many of the Wall Street financiers who have been mainstays of Republican “super PACs” in the six years since the Supreme Court’s Citizens United decision have rallied behind Senator Marco Rubio of Florida, betting that he is the party’s best chance to win a general election battle against Hillary Clinton.

In the last six months of 2015, F.E.C. records show, a “super PAC” backing Mr. Rubio raised $14.3 million, including $2.5 million each from the hedge fund founders Paul Singer and Ken Griffin. The super PAC also drew significant support from donors who previously gave to groups backing Jeb Bush, among them Chris Cline, a coal executive, and Brian Ballard, a prominent Florida lobbyist.

But the steady rise of Senator Ted Cruz of Texas, a Tea Party favorite reviled by party leaders, has unleashed a new counter-establishment of conservative donors, some from outside the universe of traditional Republican giving. They include wealthy evangelicals, libertarian businessmen, Israel hawks and others disenchanted by the party’s past nominees, and are drawn to Mr. Cruz’s uncompromising social conservatism and his promise to disrupt the party’s traditional power brokers in Washington.