Democrat Russ Feingold continues to raise more money than his opponent Sen. Ron Johnson, but outside groups are tipping the spending scale toward the incumbent Republican.

Johnson reported Thursday that he raised $4 million in the three-month period ending in September. Feingold raised $5.2 million over the same period.

That was his highest quarter of the campaign for both Johnson and Feingold. Johnson's campaign says he has $5.4 million cash on hand for the final weeks of the campaign. Feingold has not released his cash on hand amount, which must be reported by Oct. 27.

To date, Feingold has raised about $2.2 million more than Johnson in their rematch. But outside groups have spent about five times as much to help Johnson.