Mike Bloomberg, the billionaire former mayor of New York who had hoped to self-fund his way to the Democratic presidential nomination but was spurned by voters in Tuesday's balloting, has dropped out of the race.
Mr Bloomberg endorsed Joe Biden, saying the former US vice president had the best chance to win in November.
"I've always believed that defeating Donald Trump starts with uniting behind the candidate with the best shot to do it. After yesterday's vote, it is clear that candidate is my friend and a great American, Joe Biden," Mr Bloomberg said in a statement.
He will put his resources "in the broadest way possible behind Joe Biden's candidacy", said Tim O'Brien, a senior adviser to the Bloomberg campaign.
"We have long-term leases and long-term contracts with the team and the intention was always to put this big machine we have built behind whoever the nominee is."
Mr Biden, in turn, has signalled he will welcome Mr Bloomberg's financial support, drawing a sharp contrast with Senator Bernie Sanders, whose advisers have said they would reject any independent assistance from the billionaire.
"This race is bigger than candidates and bigger than politics," Mr Biden declared in a tweet addressed to Mr Bloomberg yesterday morning. "It's about defeating Donald Trump, and with your help, we're gonna do it."
Mr Bloomberg, a media tycoon worth an estimated $60bn (€54bn), entered the race in November and quickly spent hundreds of millions of dollars of his own money to flood social media, television and radio with ads that boasted "Mike Will Get It Done".
Through exorbitant sums of money and despite skipping the first four state nominating contests, Mr Bloomberg managed to rise in national polls, earning the ire of fellow candidates who accused him of trying to buy his way to the nomination.
His unconventional schedule also meant Bloomberg avoided any truly unscripted public appearances until the February 19 Democratic debate in Las Vegas when he appeared stoic and shaky in a performance that was widely panned. (© Washington Post)