CNN  — 

The Lincoln Project, the super PAC that has produced a steady stream of ads that slam President Donald Trump, saw its fundraising soar to more than $16.8 million during the second quarter, a new filing shows.

Its single largest donor in the April-to-June fundraising quarter: Connecticut-based hedge fund manager Stephen Mandel, who donated $1 million to the group. Mandel is a Democratic donor who has supported Democratic presumptive nominee Joe Biden’s presidential bid, Federal Election Commission filings show.

Mandel did not immediately respond to an interview request.

Another billionaire Democrat, Hollywood film magnate David Geffen, is among the donors who contributed $100,000. Josh Bekenstein, co-chairman of private-investment firm Bain Capital, also donated $100,000.

The super PAC is overseen by Republicans and ex-Republicans, and those associated with the group include George Conway, whose wife Kellyanne Conway is a top adviser to the President. Other key players in the Lincoln Project include Steve Schmidt, John Weaver and Reed Galen, who had ties to the late Arizona Sen. John McCain, a frequent target of Trump attacks.

The Lincoln Project’s second quarter haul far surpasses the $1.9 million the group collected in the first quarter of the year. It launched late last year.

Nearly half of the super PAC’s second-quarter contributions – roughly 45% – came in small-dollar donations. The group started July with more than $10 million in available cash.

The group has produced an array of scorching ads, that range from slamming Trump’s response to the coronavirus pandemic to attacking Republican senators who have stood with the President. The ads have drawn an angry rebuke from Trump himself, who has labeled the group “Losers Project” and called its founders Republicans in name only.

CNN’s David Wright contributed to this report.