Wisconsin Sen. Ron Johnson announced Thursday that he raised $4 million in the third quarter of 2016, less than the $5.2 million his Democratic opponent, Russ Feingold, said he raised over the last three months.

The incumbent Republican has been outraised by former Sen. Feingold over the last two years. Johnson has raised $15 million over the past two years, while Feingold has raised more than $20 million.