Matt Stone/The Boston Herald/AP Photo

Elizabeth Warren, the Democratic challenger for Senate in Massachusetts, out-raised Republican incumbent Sen. Scott Brown by nearly $5 million in the third quarter of 2012, according to figures provided by both of their campaigns.

Warren's campaign raised $12.1 million for the months of July, August and September. The campaign reported that September was its best month by far, at $7 million. Warren's campaign had $7.28 million cash on hand by the end of the quarter, but campaign officials note to ABC news that they had already pre-paid over $3 million in advertising to cover the next three weeks.

Brown raised $7.45 million for the quarter, but they ended the quarter reporting a larger amount in cash on hand than Warren- $10.2 million. The Brown campaign reported that nearly 60 percent of its contributors were from Massachusetts. The Warren campaign did not provide a percentage breakdown, although it did say that more than 53,000 residents of the state have contributed to the campaign.

The Massachusetts Senate race is so far the most expensive Senate race in the country this year in terms of money raised. Prior to the latest reports, $53 million had been taken in collectively. Polling has continuously shown the race to be close, and it's expected to stay that way through Election Day.

The Real Clear Politics polling average shows Warren with a narrow lead in the race in recent weeks, 48.5 percent to Brown's 46 percent.

ABC News rates the Massachusetts Senate race as a toss-up.