Mike Bloomberg spent more than $1 billion on four-month presidential campaign according to filing

Former New York City Mayor Mike Bloomberg spent more than $1 billion on roughly 100-day presidential run, according to a new Federal Election Commission filing.

Bloomberg poured more than $1 billion of his own money into his White House bid, which featured a national campaign operation with roughly 2,400 staff.

By the end of March, the campaign committee reported spending more than $1 billion of that money, including $158 million just in the month of March alone.

The former New York City mayor won just 55 delegates in the primary, and only one contest, in American Samoa, spending roughly $18 million per delegate.

The upwards of $1 billion Bloomberg spent in just a little more than three months of his presidential bid surpasses the total amount of spending reported so far by rest of the entire Democratic presidential field, including about $340 million from another billionaire dropout, Tom Steyer.

Since January 2019, contenders in the Democratic presidential primary -- excluding Bloomberg -- have so far reported spending just under $970 million. Some big-spending candidates including Steyer, Joe Biden and Elizabeth Warren, have yet to file their reports that cover the month of March, so the primary field total could near or surpass the Bloomberg campaign's total spending.

During the 2008 presidential election, the Obama campaign spent $760 million over the entire cycle, from the primary to the general election, and during the 2016 election, the Clinton campaign only spent $585 million throughout the primary and general election, campaign disclosures show.

After vowing to keep his campaign infrastructure running and offices around the country open through the general election to help defeat Trump, Bloomberg decided instead to transfer $18 million to the Democratic National Committee through a transfer from his campaign, a move campaign legal experts criticized given the limits on individual campaign contributions.

The move infuriated laid-off staff who said they were promised jobs through the general election, prompting lawsuits from former campaign organizers accusing Bloomberg of reneging on his pledge to pay them through November.