Ways and Means Chairman Paul D. Ryan’s stature as a GOP rainmaker is one reason so many of his colleagues want him to run for House speaker, now that California’s Kevin McCarthy has dropped out.

Ryan has said repeatedly that he is not running for speaker, but his colleagues have mounted a concerted campaign to draft him.

The Wisconsin Republican and former vice presidential candidate has raised $40 million over the course of his 17-year career on Capitol Hill for his campaign and his leadership PAC, according to the nonpartisan Center for Responsive Politics, which tracks political money.

That’s not as much as the $97 million that outgoing House Speaker John A. Boehner of Ohio collected over the course of his close to 13 terms in Congress, CRP data show. Nor has Ryan been as generous as Boehner in his contributions to GOP colleagues and party committees. Boehner has given out some $41 million over his career, according to CRP, compared with $8.2 million that Ryan contributed.

But Ryan has a deep bench of support both among K Street lobbyist bundlers and among top corporate donors around the country, thanks to his previous perch at the helm of the Budget Committee and now of the tax-writing Ways and Means Committee and to his national campaign with GOP presidential nominee Mitt Romney in 2012.

Ryan helped Romney raise $389 million for his presidential campaign, and also helped the Republican National Committee break fundraising records as chair of the RNC’s so-called Presidential Trust, which raises money for the GOP’s presidential nominee. Ryan did such a good job at the Presidential Trust in 2012 that RNC Chairman Reince Priebus tapped him to head it again in the 2016 elections.

“With Paul’s help in 2012, we shattered fundraising records and outraised the DNC, $291 million to $179 million,” said Priebus on announcing in January that Ryan would return to the post. “I look forward to working with Paul to raise the bar even higher this year and ensure that we send a Republican to the White House in 2016.”

Ryan gets most of his money from donors in the health care industry, particularly hospitals and nursing homes; on Wall Street; and in the insurance and real estate sectors, according to CRP. His receipts in the 2014 election cycle for his re-election campaign and leadership PAC, which is known as Prosperity Action, totaled $13.1 million.

By contrast, many of the other House Republicans whose names are being floated for the speakership have campaign and leadership PAC receipts more in the $1 million range. These include GOP Reps. Jason Chaffetz of Utah; Daniel Webster of Florida, and Lynn Westmoreland of Georgia.

Rep. Marsha Blackburn, R-Tenn., has raised $2.3 million for her campaign and leadership PAC in the same period. Education and Workforce Chairman John Kline, R-Minn., has pulled in $3.1 million, and Rep. Darrell Issa, R-Calif., has raised $4.4 million. By way of comparison, Ryan’s approximately $13 million haul for the 2014 cycle exceeds all six of those GOP House members combined.