Democratic Sen. Gary Peters of Michigan reports that his campaign raised $7.4 million in the first half of October.
The first-term incumbent is locked in a competitive, expensive race with Republican challenger John James.
Total spending is expected to top $100 million in the contest that will affect which party takes the Senate majority, which is now held by the GOP.
Peters has led or been slightly ahead in recent polling. Peters’ campaign manager Dan Farough says the latest fundraising total makes “clear that the momentum and grassroots energy” is with the senator.