Michael Bloomberg, the former New York city mayor, has announced he will not run for the US presidency in 2020, defying widespread predictions of his candidacy.
Mr Bloomberg said that while he thought he could beat Donald Trump he was not sure he would win the Democratic nomination given the competitive field.
Instead Mr Bloomberg pledged to spend his next two years pushing for the policy changes, such as tighter gun controls and tackling climate change, in which he believes.
“As I’ve thought about a possible presidential campaign, the choice before me has become clear,” Mr Bloomberg in a 1,400-word article outlining his thinking.
“Should I devote the next two years to talking about my ideas and record, knowing that I might never win the Democratic nomination?
“Or should I spend the next two years doubling down on the work that I am already leading and funding, and that I know can produce real and beneficial results for the country, right now?”
He had also recently registered as a Democrat, another indication that he was preparing to seek the party’s nomination. He has previously seriously considered an independent bid for the presidency.
The decision reflects the crowded field already in place on the Democratic side, with more than a dozen candidates running including a string of prominent senators.
But it may also have been influenced by the drift to the Left of the party on economic and health care issues, as well as signs that Democrat activists are looking for a candidate who embodies change.
Writing for Bloomberg, the media arm of his organisation, Mr Bloomberg acknowledges that he would have to tailor his policy beliefs if he was to win the Democratic nomination.
“Many people have urged me to run. Some have told me that to win the Democratic nomination, I would need to change my views to match the polls. But I’ve been hearing that my whole political career,” Mr Bloomberg said.
“I’ve run for office three times and won each time, in no small part because I’ve never stuck my finger in the wind to decide what I should believe. It’s not who I am, nor do I think it’s what voters want in a leader.”
Elsewhere he acknowledged: "I am clear-eyed about the difficulty of winning the Democratic nomination in such a crowded field."
Mr Bloomberg said instead he will push for the policy issues he believes in. Fighting climate change, tightening gun control, improving public schools, tackling opioid addiction and strengthening local communities were all mentioned.
He finished his statement saying: “While there would be no higher honor than serving as president, my highest obligation as a citizen is to help the country the best way I can, right now.”