HELENA - With more than $731,000 in the bank on March 31, Republican U.S. Rep. Denny Rehberg again has amassed the largest campaign war chest in the House race, reports filed Thursday showed.

Four Democrats and three Republicans, including Rehberg, are running for the House seat. Libertarian Mike Fellows will be on the November ballot.

The five-term Republican congressman reported total campaign donations topping $783,000 and expenses exceeding $672,000 as of March 31, Federal Election Commission reports show. Leftover money from his 2008 campaign has helped give his 2010 campaign more than $731,000 in cash in the bank.

For the first three months of this year, Rehberg raised more than $153,000 and spent nearly $161,000.

"Montanans have become increasingly concerned about the direction our country is headed, and they're standing behind Congressman Rehberg's strong record of fiscal discipline," said his campaign manager, Tyler Matthews.

Rehberg's massive lead in fund-raising is not unexpected. Incumbents nearly always are able to raise more money than their opponents.

On the Democratic side, where candidates have been critical of Rehberg's fiscal record during the administration of Republican President George W. Bush, two candidates lead the field.

Tyler Gernant, a Missoula lawyer, had the most cash left in the bank with more than $24,000 as of March 31.

However, Dennis McDonald, a Melville rancher, has raised the most money for the campaign at more than $128,000 and for the quarter with net donations of $24,300.

Gernant has collected more than $101,000 for the campaign and spent nearly $77,000 so far to leave about $24,000 in the bank as of March 31. He has made more than $1,800 in loans to his campaign, although none during the current quarter. Gernant also has donated more than $1,700 to his campaign, including $182 in the most recent quarter.

For the first quarter of 2010, Gernant raised more than $23,500 and spent nearly $24,000.

"We are pleased with our most recent numbers," Gernant said. "Contributions were strong in March and we expect the trend to continue through the primary election in June."

McDonald, for the full campaign, has collected about more than $128,000 and spent $123,000. He reported having nearly $16,200 in cash on the bank as of March 31 in part because of a $9,838 loan he made to his campaign during the past three months. He made a $1,000 loan to his campaign in an earlier quarter.

For this quarter, McDonald showed more than $24,200 in net donations and $36,000 in expenditures.

McDonald said the first three months of 2010 were not his best quarter, but said he is raising a higher proportion of dollars from Montanans than is Rehberg.

"When I started this race, I had no idea it would be this difficult to raise substantial monies," he said. "What I've learned is it's the toughest economic time to raise money probably going back 80 years."

Republican A.J. Otjen, a Republican college professor from Laurel, has raised more than $5,700, including a $2,228 donation from herself for the quarter and spent more than $6,800. She listed a cash balance of $2,050, which was boosted by the more than $3,100 the campaign had left in the bank on Dec. 31.

Otjen said she has been focusing on her teaching at Montana State University-Billings, but that classes are over in a week. After that, she said she will be able to campaign full-time. She said she is getting a good reception from the Montanans she meets.

Democrat Sam Rankin, a Billings real-estate broker, who jumped in the race last month, had no net contributions. He loaned his campaign $8,639, which is the entire amount received by his campaign so far. He has spent $5,404 to leave a cash balance of $3,235 as of March 31.

"For people focused on money as the indicator of a high-quality, worthwhile politician, I ask, ‘How's that been going lately?'" Rankin said.

Republican Mark French, a clinical laboratory scientist from Paradise, said his campaign report was sent by certified mail to the FEC, although the fund-raising summary doesn't appear yet on the FEC Web site. French didn't have these fund-raising numbers available immediately because he was on the road campaigning.

Likewise, the FEC Web site didn't show a report yet from Democrat Melinda Gopher, a Missoula paralegal, by Thursday afternoon. She was on her way to a campaign event in Bozeman and could not be reached.

Candidates do not have to file an FEC report until they have raised or spent $5,000.