Bloomberg is spending in all the 50 US states but was especially targeting the big, delegate-rich Super Tuesday states that can make or break his campaign, such as California, Texas and Florida, Xinhua news agency reported citing Politico as saying in a report on Wednesday.
The Politico report said that the former Mayor's spending on ads in the roughly three weeks since late November was more than double the combined ad spending of every single non-billionaire candidate in the Democratic field this entire year.
"We've never seen spending like this in a presidential race," Jim McLaughlin, a Republican political strategist who worked as a consultant for Bloomberg's mayoral bids in New York, was quoted as saying.
"He has a limitless budget."
But some analysts were sceptical whether the big spending on ads would help improve Bloomberg's standing in the poll.
"After you see the same TV ad 10 times, it's not going to have as big an impact," Christian Heiens, a political marketer with Saber Communications, was quoted as saying.
"And that's not just in politics, that's in anything in marketing."
In the Democratic primary race, former Vice President Joe Biden leads the field with 30 per cent of the vote among Democratic voters and independent voters who lean towards the party, according to a Quinnipiac University national poll released last week.
Biden is followed by Senator Elizabeth Warren with 17 per cent of the vote, while Bloomberg is in the fifth place with only 7 per cent of the vote, the poll showed.
( With inputs from IANS )