Democratic Senate candidate David Hoffman reported Monday that he has raised $905,137 in the month since announcing his candidacy for the seat currently held by Roland Burris.
More than half of that total, however, came from a $500,000 personal loan to the campaign.
The former federal prosecutor resigned in August after four years as Chicago's inspector general to make his first run at elected political office.
The Hoffman campaign says that none of the money came from political action committees or registered lobbyists, from whom he has vowed not to accept a dollar.
Hoffman said he loaned himself half-a-million dollars in a bid to catch up with state Treasurer Alexi Giannoulias, who was the first Democrat to enter the race and who is far ahead of Hoffman in fund-raising.
Hoffman, who was endorsed last week by former federal judge and Congressman Abner Mikva, is attempting to cast himself as the reform candidate.
"Mark Kirk and the Republicans would love to run against Democratic corruption instead of defending their opposition to health care reform and tougher regulation of Wall Street," Hoffman said in a statement. "They can't make that case against me, and that's why my nomination would be a serious threat to their effort to win this Senate seat."
Former Chicago Urban League president Cheryle Robinson Jackson and Chicago attorney Jacob Meister are also seeking the Democratic nomination for President Obama's old Senate seat.
Congressman Mark Kirk, the GOP frontrunner, announced Monday he raised $1.6 million in the third quarter of 2009 and has $2.3 million in the bank.
Official reports of candidates' third quarter fund-raising will be released later in October.