Democratic challengers raise hefty sums for campaigns against Republican incumbents

As early fundraising figures begin to pour in, several Democratic challengers to incumbents appear to be raising hefty sums, the figures in a year in which some races are seeing eye-popping sums.

Here are several notable mentions:

U.S. Rep. Beto O’Rourke

Democratic U.S. Rep. Beto O’Rourke continues to capitalize on his grassroots campaign against Sen. Ted Cruz in Texas, raising more than $6.7 million from 141,000 contributions during the first quarter of 2018, according to his campaign.

O’Rourke, who has continuously been outraising the GOP incumbent since last year, raised about $4 million just in the month of March, since after the primary.

“We’re absolutely running this race the right way – not taking any PAC money, going to every single county and holding town halls across Texas where anyone can ask any question,” O’Rourke said in a statement.

Randy Bryce

A Democratic House campaign challenging the most powerful Republican in Congress, Speaker Paul Ryan, has also enjoyed momentum since the beginning of this year.

An ironworker and Army veteran in Wisconsin, Randy Bryce raised $2.1 million and added 45,000 new donors to his campaign in the first quarter of 2018 in his bid to unseat Ryan, who has represented the district since 1999, Bryce's campaign announced Monday. With his recent fundraising uptick, Bryce has raised $4.75 million since June 2017 according to filings with the Federal Elections Commission (FEC).

Andrew Janz

In a deep-red district in inner California, the Russia investigation is stirring up what was supposed to be a smooth reelection bid for eighth-term GOP Rep. Devin Nunes. Democratic challenger Andrew Janz has collected more than $1 million in the first quarter of 2018, mostly through small online contributions.

Janz has attributed the uptick in donations to his campaign to a controversial memo written by Republican staff on the House Intelligence Committee, chaired by Devin Nunes, R-Calif., alleging political bias and abuses of government surveillance powers at the FBI and Justice Department. Janz's campaign manager Heather Greven told ABC News that he raised about $160,000 just the day after the release of the memo.

Like O'Rourke, Janz touts support from small grassroots donors, rejecting big checks from corporations and PACs.

J.B. Pritzker

Meanwhile, in Illinois gubernatorial race, Democratic nominee J.B. Pritzker has dropped another jaw-dropping $7 million from his own pocket to his campaign against Republican Gov. Bruce Rauner. The latest generosity adds to nearly $70 million the billionaire entrepreneur has already put in the race so far.

With determined Rauner also pumping more than $50 million of his own money into keeping his seat, the Illinois gubernatorial race has quickly risen to be one of the most expensive races of the American history.

Cruz, Ryan, Nunes and Rauner have not released their latest fundraising figures yet.