President Obama’s campaign raised more money in September than any candidate has raised in a previous month this year, according to several Democrats familiar with the campaign’s money-raising operation.
Several sources said the president’s haul last month exceeded the $114 million he raised in August, in part on the strength of donations that flowed in after the Democratic National Convention and former president Bill Clinton’s well-received speech.
One Democrat familiar with the fund-raising effort said Mr. Obama and his allies at the Democratic National Committee raised more than $150 million in September.
Officials with the campaign declined to comment on the news, which was first reported by The Wall Street Journal. One Democratic source said aides were still tallying the funds raised in September ahead of the official report they must submit later this month.
Mr. Obama edged out Mitt Romney’s $112 million in August. In 2008, Mr. Obama had the biggest month ever for any presidential candidate, raising $193 million that September.
This year’s haul signals a boost in financial support for Mr. Obama as he nears the conclusion of his battle with Mr. Romney in a little over a month. It ensures that Mr. Obama will have plenty of money for the balance of the campaign despite having been outraised by his Republican rival throughout the summer.
And it comes as Mr. Obama’s campaign confronts the president’s lackluster performance at the first presidential debate Wednesday night.
Mr. Romney’s campaign did not release any information about its fund-raising on Thursday.
Mr. Obama’s advisers have long warned that Mr. Romney’s fund-raising prowess and the success of Republican “super PACs” that are backing him threatened to put the president at a financial disadvantage going into the final stretch.
In fact, it appears to be Mr. Romney who has struggled to keep up. Mr. Obama’s campaign has run far more ads than Mr. Romney in the last several weeks. And the president’s ground operation — which was built over the course of several years — is far larger than Mr. Romney’s.
The never-ending money chase is largely Mr. Obama’s own doing. By choosing to reject federal campaign funds in 2008, Mr. Obama effectively condemned himself — and his future rival — to a continuing need to raise money all the way to election day. (Senator John McCain of Arizona chose to take the federal money in 2008 and was vastly outspent.)
Now, both Mr. Obama and Mr. Romney have continued to hold fund-raisers and make appeals to their supporters for cash even as they hold big rallies in battleground states across the country.
Mr. Obama’s apparent success in September may be a result of a surge in small donors, who have long been a vital part of the president’s financial base. The campaign said on Monday that it had collected money in more than 10 million individual donations, a record.
By contrast, Mr. Romney has tended to rely more on fewer — but wealthier — donors. That has meant that more of Mr. Romney’s money is housed at the Republican National Committee, which, by law, can accept much larger contributions from individuals.
Follow Michael D. Shear on Twitter at @shearm.
