Rep. Anthony Weiner, who started as an underdog in the 2005 Democratic mayoral primary, but led a come-from-behind campaign that nearly won him the nomination, is now leading the fund-raising race for the 2009 election.

An aide to Mr. Weiner said the congressman, whose district includes parts of Queens and Brooklyn, raised more than $2 million during the latest six-month fundraising period, which ended last night. The preliminary numbers from the period indicate he has out-raised the Democrats presumed to be his leading rivals.

The strong showing is a boon for Mr. Weiner — who scored points with Democrats for bowing out of a potential 2005 primary runoff with eventual nominee Fernando Ferrer for the sake of party unity — and give him an immediate advantage.

Sources close to the speaker of the City Council, Christine Quinn, say she raised about $1 million for her mayoral campaign between January and July, and has about $200,000 more in the bank from previous fund-raising. The president of the Bronx, Adolfo Carrión, raised about $1 million for this period.

A source close to the city’s comptroller, William Thompson Jr., said he took in $750,000 in the last six months. That source said that Mr. Thompson has raised more cash overall than any other candidate because he has $3.1million for the race, which currently has a spending limit of $5.7 million in the primary. Mr. Thompson transferred $1.3 million from his last race for comptroller and raised money in the previous fund-raising cycles for 2009 race. The Thompson source said the “point is getting to $6 million,” and noted that the comptroller is more than halfway there.

This fund-raising period is already being viewed as the first real benchmark for the 2009 primary because it offers the first glimpse into where prospective candidates are getting financial support, how much money they can rake in, and how many donors they have.

“If you’re a serious candidate you have to be putting money in the bank in a consistent way, starting with this filing,” a political consultant and lobbyist, Scott Levenson said.

Mr. Levenson said that while “you can’t argue” with the fact that Mr. Thompson has more total money, he said that $750,000 is “less than impressive for the comptroller,” particularly because some consider him the early frontrunner.

The president of Brooklyn, Marty Markowitz, who is also considering a run, could not be reached last night. Neither could the public advocate, Betsy Gotbaum, who has been named as a possible candidate.

Earlier this week, Mr. Markowitz said he’s only held one fundraiser, which was hosted by Mr. Bloomberg, during the period. “That raised between $325,000 and $350,000,” he said. He did not say how much money he raised otherwise.

Meanwhile, City Council Member Eric Gioia, who is said to be planning a race for public advocate, raised $250,000 for this period, bringing his total to about $1.2 million. City Council Member Simcha Felder, who has indicated that he may run for comptroller, raised about $700,000 in the last six month, adding to the $381,000 he raised in the previous filing period.

Candidates have until Monday to turn fund-raising records into the CFB.