A Republican super PAC that couldn't seem to break the six-figure mark throughout 2018 has just been given a boost with 11 days until the midterm elections.

Future45 loaded its war chest in October, with the likes of banking executive Charles Schwab and hedge-fund manager Paul Singer each giving $1 million to the organization, according to a new Federal Election Commission filing. TD Ameritrade founder Joe Ricketts donated $900,000.

Representatives for Schwab and Singer did not return a request for comment. Ricketts could not be reached.

With their contributions, along with six-figure payments by the wives of Schwab and Ricketts, the PAC raised over $5 million in one month.

Their targets this year have included the likes of liberal Democratic candidate for Congress Alexandra Ocasio-Cortez, Sen. Bernie Sanders and House Minority Leader Nancy Pelosi, among other high-profile Democratic lawmakers, according to the nonpartisan Center for Responsive Politics.

In 2016, the PAC saw contributions from the likes of GOP megadonor and casino magnate Sheldon Adelson. While he has not contributed to the PAC this time around, he's become the top donor in the midterms. Records show Adelson and his wife, Miriam, have given in excess of $80 million.

The surge in the PAC's contributions comes as political financiers from both sides of the aisle begin a final blitz of spending in order to push their respective sides over the finish line come November.

Billionaire Democrat Tom Steyer is preparing to invest $16 million in the runup to the general election, CNBC first reported. Billionaire and former New York Mayor Mike Bloomberg spent over $42 million in October backing Democrats and added another $10 million to his super PAC Independence USA on Friday.

Many Republican donors such as Robert Mercer, former CEO of hedge fund Renaissance Technologies, and Blackstone CEO Steve Schwarzman have also attempted to give a boost to their side but have given far less than their Democratic counterparts this month and throughout the election season.

Mercer contributed $400,000 in October to the Congressional Leadership Fund, a super PAC supporting Republicans running for the House of Representatives.

Schwarzman donated $3 million to the Senate Leadership Fund, an organization backing GOP candidates trying to get into the Senate, in October. He also gave $1 million to the Congressional Leadership Fund in October.

The two have combined to give just over $9 million this cycle, according to the Center for Responsive Politics.

Republican strategists believe that the lack of cash from some of the party's top donors has left GOP candidates struggling to make inroads in 2018.

"The Bloombergs of the world, Steyers of the world, they were all in. Our side, they got a little bit complacent," said a top Republican advisor, who declined to be named because of his involvement with the midterms.