"He has been very clear and explicit that he is not running for president," Bloomberg's Press Secretary Stu Loeser, told The Washington Post.
The Post quoted a friend of Bloomberg, who said a presidential run is "still on his mind."
If U.S> Sen. Hillary Clinton, D-N.Y., wins the Democratic nomination, and Bloomberg's mayoral predecessor Rudy Giuliani wins the Republican nomination and Bloomberg decides the enter the race as an independent candidate, there's a possibility of a presidential ticket bearing three New Yorkers.
"It's the water," former New York Mayor Edward Koch told the Post. "There's no lead in it, which can cloud your thinking."
Bloomberg, founder of financial software service Bloomberg L.P., is a self-made billionaire worth about $5.5 billion, so he could finance a presidential run.