The billionaire has broken his own spending record from four years ago, dropping $85.2 million on his campaign for a third term with 11 days to go until Election Day.
The popular billionaire was 16 points ahead of Democrat William Thompson Jr. in a poll released this week but has been spending at a rate of more than $850,000 a day.
A finance report filed by his campaign for a Friday deadline covers Bloomberg's expenses since Sept. 29. He spent $20.4 million in that period, helping him shatter his $85 million record from 2005. He spent $74 million on his first run in 2001.
Thompson, who had been having trouble raising money, reported raising $270,000. He has spent about $6 million of the $8 million he has collected in donations and matching funds. His fundraising continues to lag behind previous Democratic nominees.
Over the most recent 21-day period evaluated, Thompson spent $270,000, compared with $543,511 spent by Mark Green in 2001 and $696,240 spent by Fernando Ferrer in 2005.
The mayor, whose estimated $17.5 billion fortune makes him the wealthiest person in New York City, does not take donations and can spend his money as he wishes. He must report his expenditures to the city's Campaign Finance Board.
He defends his exhorbitant spending as a cost of running on the GOP line in a city where Democrats outnumber Republicans by a ratio of 5 to 1.
He sought to portray Thompson as having the advantage.
"This city is overwhelmingly Democratic, and so he does start out with an awful lot of people who will vote the party line ... and I have to deal with that,'' Bloomberg said this week.
"I'm not trying to spend money that I don't think is necessary,'' added Bloomberg, who is not registered with a party but is running on the Republican and Independent Party lines.
Republicans have won New York City races with far less.
In 1993, Rudy Giuliani spent $9 million and beat Democratic incumbent David Dinkins. Adjusted for inflation, that's like spending $13.5 million in 2009.
Four years later, Giuliani spent $12 million -- which is like $16.1 million today -- and sailed to re-election over Democrat Ruth Messinger, winning by double-digits.
The election is 11 days away and Bloomberg is comfortably ahead of his Democratic opponent in polls. Meanwhile, challenger Bill Thompson appears to be losing ground, according to the latest Marist poll.
More than half of likely voters support Bloomberg at 52 percent, compared to Thompson’s 36 percent. The mayor only led by 9 percentage points last month.