House Speaker Paul D. Ryan (R-Wis.) participates in an interview at the Economic Club of Washington on Sept. 28. (Gary Cameron/Reuters)

The super PAC working to protect the Republican House majority is ballooning with money from mega-donors determined to keep Paul D. Ryan as speaker, scooping up a record $31.3 million last quarter, officials told The Washington Post.

The Congressional Leadership Fund's staggering haul — more than nine times greater than what the group raised during the same period two years ago — was thanks mostly to Las Vegas casino mogul Sheldon Adelson and his wife, Miriam, who together gave the group $20 million. But several other first-time donors to the super PAC this cycle also stepped up with seven-figure checks. They include Arkansas-based poultry company owner Ronald M. Cameron ($2 million), Chicago hedge fund manager Kenneth C. Griffin ($1 million) and Houston Texans chief executive Robert C. McNair ($1 million), according to officials. The super PAC must file its latest finance report with the Federal Election Commission by Saturday.

The surge of cash was driven largely by donors who have a relationship with Ryan and see the group as one of the best ways to assist him, said Mike Shields, president of the Congressional Leadership Fund.

“We are the only super PAC whose job is to help Paul D. Ryan succeed,” Shields said, adding: “Once they understand that this is important to support him, they get on board. Donors are responding to his leadership. They are seeing in him the type of Republican leader they believe the party needs. He is pushing a positive agenda for the country.”

Another major factor: A widespread worry throughout the party that GOP presidential nominee Donald Trump's tumultuous campaign will rock down-ballot races. Even the Republican National Committee has redirected some of its resources, announcing Friday that it had transferred $4.5 million to the National Republican Senatorial Committee and $1.85 million to the National Republican Campaign Committee, a move it said was backed by the Trump campaign.

“Every one of these donors is aware of the dynamics of the top of the ticket,” Shields said.

The situation is particularly complicated for Ryan. The House speaker fielded a withering personal assault from Trump after he told fellow lawmakers Monday that he would no longer defend the GOP presidential nominee or campaign for him in the wake of The Post's report on a video of Trump making crude remarks about women. Ryan did not rescind his endorsement, however. And he told donors on a conference call Wednesday that the party could not be divided, saying the GOP had to remain focused on fighting Democrats, according to a donor on the call.

The Congressional Leadership Fund is doing its part, financing a blitz of television ads aimed at protecting GOP congressional candidates. Shields said that while the battle for control of the House has expanded into more races, he remains confident that Democrats will fall short of taking back the majority.

So far this cycle, the super PAC has spent $28 million in 22 races, including a new surge of spending in Republican-leaning districts where Democrats are on the offensive. An allied nonprofit group, American Action Network, has spent $5 million.

“I look at it as we have the luxury to do it,” Shields said. “We are now in a position where we have the ability to go in and put a blanket over more races.”

The super PAC had more than $33 million on hand at the end of September, and more money is flowing in, he said. The group's efforts have been bolstered by Mason Fink, a top Ryan ally who served as national finance director for Mitt Romney's two presidential campaigns and is now on the super PAC's board.

“Donors are standing for something,” Fink said in a statement. “Protecting a functioning majority in the House and putting Speaker Ryan in a position of strength post-election is a cause. Those focused on protecting the House Majority recognize that in order to enable an agenda, you first need to win.”