Mr. Johnson’s and Mr. Thune’s groups, the Congressional and Senate Leadership Funds, reported holding just $32.7 million and $29.7 million as of June 30. Super PACs had to file reports with the F.E.C. by midnight Thursday, detailing fund-raising and spending activity from January to June.

Billionaires Elon Musk and Jeff Yass along with crypto industry donors helped President Donald Trump raise $236 million for his political operation in the first six months of 2025 — an unprecedented sum for a second-term president.