SIOUX FALLS, S.D. (AP) — Former South Dakota Gov. Mike Rounds took in more than $516,000 in campaign contributions during the final three months of 2013, far outpacing his fellow candidates in the race for one of the state's U.S. Senate seats, according to reports filed Friday with the Federal Election Commission.

Rounds, who was the first of five Republicans to declare candidacy for the seat being vacated by Democrat Tim Johnson, has been establishing himself as the front-runner for the party's nomination with his fundraising efforts. The Pierre insurance and real estate businessman took in more than $113,000 from political action committees, including $48,500 from U.S. senators' committees, $21,000 from banking and financial service committees and $14,750 from real estate committees and insurance industry committees, according to an AP analysis of the FEC reports.

Of Rounds' nearly $406,000 in individual contributions during the quarter, $238,260 came from donors listing out-of-state addresses, with California, Massachusetts, New York and New Jersey appearing often on the ledger. His campaign shows just over $1.16 million on hand as of Dec. 31.

The lone Democrat to declare his candidacy, Rick Weiland, raised nearly $161,000 during the quarter. The campaign had $385,000 on hand as of the end of 2013, with $106,000 in debts owed by the committee. A breakdown of the individual and PAC contributions was not available because the Weiland campaign provided just a summary sheet, not the full report.

Weiland, an ex-staffer for former Sen. Tom Daschle who ran unsuccessfully for Congress in 1996, has said he is running for the seat because congressional Republicans are trying to cut education programs and have proposed changes he believes would harm Social Security and Medicare.

Former U.S. Sen. Larry Pressler, who entered the race Dec. 26 as an independent, saying he wants to end the gridlock between Democrats and Republicans, jump-started his campaign with a $25,000 loan from himself and an additional $2,250 of his own money that he paid to a Sioux Falls consulting firm. Pressler also received a $2,600 contribution from a retired Washington physician, leaving him with $27,600 on hand at the end of the year.

Pressler, who grew up on a farm west of Sioux Falls near Humboldt, served two terms in the U.S. House as a Republican from 1975 to 1979 and three Senate terms with the GOP from 1979 to 1997. He lost a 1996 re-election bid to Johnson.

Johnson chose not to seek re-election this year after three terms in the Senate.

One of Rounds' four Republican primary opponents, state Rep. Stace Nelson of Fulton, raised $31,040 in contributions from October through December, all from in-state donors.

Nelson, a semi-retired hobby farmer who served in the U.S. Marines and the Naval Criminal Investigative Service, said he's running for the Republican nomination because Congress needs someone who will stick to promises to oppose increased taxes and government spending. The state lawmaker often has quarreled with party leaders in the South Dakota Legislature. Nelson had nearly $34,000 on hand as of the end of the year.

State Sen. Larry Rhoden, a rancher and custom welder from Union Center, raised $37,740 during the quarter, according to a statement from his campaign. The reports filed with the FEC were not provided.

Rhoden's campaign said it had nearly $73,000 cash on hand as of Dec. 31. The longtime leader in the Legislature was the first to challenge Rounds for the Republican nomination.

Jason Ravnsborg, a Yankton attorney and Army Reserves major with no political experience, was not required to file FEC paperwork for the period because he entered the race on Dec. 16. Ravnsborg says he wants to cut the federal budget deficit and opposes President Barack Obama's health care law.

Sioux Falls physician Annette Bosworth, another political newcomer, did not respond to AP's request for the FEC report. The previous quarter's record shows that Bosworth received just over $50,000 in contributions after announcing her candidacy in July.