Former New York mayor Michael Bloomberg, one of the world’s richest men, announced his bid for the Democratic presidential nomination by promising to “rebuild America” and defeat President Donald Trump.

According to sources, Mike Bloomberg announced Sunday he is running for president, bringing a narrow following but boundless bank account to the crowded Democratic primary.

The announcement, which Bloomberg telegraphed for weeks even after deciding earlier this year to not run, reflects his view that the current field of Democratic candidates is not well positioned to win in 2020.

Bloomberg has promised a disruptive campaign that could break spending records with a massive advertising buy aimed at states that vote in March and April.

The 77-year-old New York City mayor, positioning himself as a centrist alternative to Joe Biden, launched his candidacy in an online video that is part personal story, part attack on President Donald Trump.

Bloomberg became one of the richest people in the world on the success of his eponymous financial news company.

He then served three terms as New York City mayor and in 2014 was honorarily knighted by Queen Elizabeth.