Republican senate candidate Matt Bevin in October 2013. (John Sommers II/Reuters)

Senate Minority Leader Mitch McConnell's (R) primary opponent, businessman Matt Bevin, raised $900,000 in the fourth quarter, according to his campaign.

About half of Bevin's total appears to have been raised by the Senate Conservatives Fund, which has endorsed his campaign and said this month that it had raised $450,000 for him. Bevin's campaign said about $430,000 of the total was raised with SCF's help.

The total doesn't include any self-funding from Bevin, who had previously loaned his campaign $600,000. His campaign did not release a cash-on-hand figure, but it had just $164,000 on hand at the beginning of October.

Bevin is very likely to be hugely outspent in the primary. McConnell already had $10.3 million in the bank at the beginning of October. He has not announced his fourth-quarter fundraising totals yet, and neither has Kentucky Secretary of State Alison Lundergan Grimes, the leading Democratic candidate.

McConnell is one of several GOP incumbents being targeted in a primary this year. Others include Sens. Thad Cochran (Miss.), Pat Roberts (Kan.) and John Cornyn (Tex.).

Updated at 12:54 p.m.