WASHINGTON — A Republican presidential candidate, Mitt Romney, reported that he is worth up to $247 million, which may make him the wealthiest of the 2008 contenders.

Mr. Romney, 60, yesterday filed documents disclosing his assets to the Federal Election Commission. The former Massachusetts governor, who won the Iowa straw poll on Saturday, reported that most of his assets are in a blind trust or retirement account. When the assets of his wife, Ann, are included, the Romneys had total holdings between $190 million and $250 million, according to national campaign counsel Ben Ginsberg.

Mr. Romney has lent his campaign a total of $8.9 million.

His reported holdings included shares worth $250,000 to $500,000 in Fairfield, Conn.-based General Electric Co. and $100,000 to $250,000 in New York-based Citigroup Inc. They also included bank and money market accounts held jointly with his wife and valued between $6.1 million and $30.3 million.

Candidates were required to file with the FEC by May 15, though Mr. Romney received two extensions. The candidates are required to value their holdings in broad categories.

Mr. Romney’s financial holdings may be greater than the other major Democratic and Republican contenders combined. Mayor Giuliani reported assets of as much as $70 million. Senator McCain of Arizona reported personal assets of up to $80,000, though his wife had millions of dollars in holdings, including a beer distributorship.

On the Democratic side, Senator Clinton of New York reported that she was worth up to $51 million. A former North Carolina senator, John Edwards, reported assets of $30 million, while Senator Obama of Illinois said he was worth up to $1.1 million.

Mr. Romney had $12 million in his campaign bank account as of June 30, trailing only Mr. Giuliani, who had $15 million. Mr. McCain had $2 million in cash for the primaries. Mr. Romney kept pace with Mr. Giuliani by reaching into his own pocket during both fund-raising periods, lending his campaign a total of $8.9 million.

The Romneys’ investment decisions are made by a trustee without their knowledge, and they are not given a list of their holdings, the report stated.

Mr. Romney founded the Boston-based venture capital firm Bain Capital LLC and will continue to receive profits from some of the group’s funds through February 11, 2009. Neither he nor his wife is involved in any transactions involving those funds, nor do they know their holdings, he reported.