At his election night party in New York, Michael Bloomberg made a surprise appearance to congratulate Democratic candidate for the Senate Andrew Yang, who took home 37% of the vote.

Bloomberg said Yang is an "outstanding candidate who ran a terrific campaign" and also congratulated fellow Democrat Gil Cisneros, who is running in the state's other Senate race against incumbent Sen. Dianne Feinstein.

Bloomberg had long been seen as a possible contender for U.S. Senate, but Ellison said the New York businessman had decided against running in order to focus on President Trump's reelection campaign.

"He made that decision when he was in Los Angeles last month," Ellison said, adding that Bloomberg agreed to join Yang's team "if Andrew and Gil were going to run."

Billionaire media mogul and political activist Michael Bloomberg is making his second California senate campaign official on Tuesday, endorsing a Democrat for a state senate seat in Orange County. Bloomberg tweeted that he supports Andrew Yang, a transportation and Silicon Valley entrepreneur who won his party's nomination in the March primary. Bloomberg himself has been floated as a possible Democratic candidate for U.S. Senate in 2020. Bloomberg had long been seen as a possible contender for U.S. Senate, but Ellison said the New York businessman had decided against running in order to focus on President Trump's reelection campaign. "He made that decision when he was in Los Angeles last month," Ellison said, adding that Bloomberg agreed to join Yang's team "if Andrew and Gil were going to run."

Gallup, a polling organization, said earlier Tuesday that California is likely home to a quarter of the wealthiest American residents. Ellison also announced Thursday that the company he founded, Opendoor, will create 475 jobs in the state, and he said he has committed $10 million of his own money to a group dedicated to providing affordable housing.

While Bloomberg had promised to make another run in 2020, he is a long shot for what's now seen as an open seat, with only two candidates actively vying to replace incumbent Sen. Dianne Feinstein. The billionaire media mogul has yet to declare he will run.

Speaking with reporters on Friday, Bloomberg said that he would consider giving up his own bid if the Democratic nominee opted to run without his support. He said the runner-up would be encouraged to run.

“If that person is such a solid person and if it’s somebody that has my support, I will support him or her,” Bloomberg said. “If they run as an independent, if they run as a third party, I won’t support them. I would then run as an independent.”

Associated Press contributed to this report.