According to Advertising Analytics, Bloomberg's campaign had spent more than $57.5 million on TV ads, more than three times the spend of the Trump Make America Great Again Committee ($19 million). The pro-Trump committee was followed by South Bend, Ind. Mayor Pete Buttigieg at $15.6 million and Sen. Bernie Sanders, I-Vt. at $14 million.
Bloomberg narrowly trailed fellow billionaire Tom Steyer, who had spent nearly $60.2 million on ads.
CNBC reported that Bloomberg's ad spending included $6 million in national television spots, more than $4 million in Texas ads, and $3 million focused on New York and Los Angeles.
Trump's campaign, which already has the full support from the Republican Party, has been working with the Republican National Committee to raise a record amount of funds -- amassing an enormous war chest against whoever the Democratic nominee will be.
Bloomberg entered the 2020 presidential race relatively late and needs to make gains in the polls if he wants to keep up with the party's frontrunners.
Bloomberg's investment was the most any candidate ever spent in a single week of advertising, according to Advertising Analytics. And according to market research data, Bloomberg's ads ran 19,006 times between Nov. 23 and Dec. 1.
The massive amount of spending will likely intensify progressive attacks on the former mayor.
Sanders has already accused Bloomberg of trying to "buy this election." Fellow progressive Sen. Elizabeth Warren, D-Mass., similarly attacked the billionaire turned presidential candidate.
Prominent Sanders supporter Rep. Alexandria Ocasio-Cortez, D-N.Y., appeared to accuse Bloomberg of trying to "purchase our political system" at a recent rally in Iowa.
"There are folks that are trying to completely purchase our political system, running as Republicans and now tossing in their hats as Democrats in the field as well," she said.
"But what we're here to say is that in a democracy, it shouldn't matter how much money you have. What should matter is whether you vote, whether you caucus, whether you turn out. It's the numbers. It's the people. it's the movement."