After a month of mulling, Mitt Romney said Friday that he will not be a candidate for president in 2016. Alex Wong/Getty Images

After a month of mulling, Mitt Romney will not mount a third presidential bid. The 2012 GOP nominee gave supporters the news in an 11 a.m. EST conference call on Friday.

"After putting considerable thought into making another run for president, I’ve decided it is best to give other leaders in the party the opportunity to become our next nominee," Romney said.

Throughout the month, Romney was weighing the pros and cons of a 2016 campaign -- and the cons won out. A major calculation was the belief that a bruising Republican primary would damage Romney so badly that he would have no chance in a general election against Hillary Clinton, who is widely expected to run for the Democratic nomination and win, according to Bloomberg. While Romney would have faced almost a half-dozen credible candidates, there is no strong opposition to Clinton, and she could focus her energy and money on the general election in a way that Mitt couldn’t.

Family considerations, especially the stress of a grueling campaign, was also said to be one of Romney’s major reasons for not announcing a candidacy. “While to the Romneys the call to service rings loud and true, the prospect is daunting to the entire family,” Bloomberg reported.

Former Florida Gov. Jeb Bush, who would have been one of Romney's potential rivals for the 2016 nomination, praised Romney in a statement. "Mitt is a patriot and I join many in hoping his days of serving our nation and our party are not over," Bush said in a Facebook post. "I look forward to working with him to ensure all Americans have a chance to rise up."

U.S. Sen. Rand Paul, R-Ky., another possible 2016 GOP candidate, tweeted that he hopes "to work together with Mitt to grow our party and lead our country forward."

Up until December, the thinking was that Romney was averse to running in 2016. Last year, he said “No” 11 times in a New York Times interview about whether he would launch a third consecutive campaign. “Oh, no, no, no. No, no, no, no, no. No, no, no. People are always gracious and say, ‘Oh, you should run again.’ I’m not running again,” he said.

In the Netflix 2014 documentary, “Mitt,” Romney also hinted at Friday’s decision. “I have looked, by the way, at what happens to anybody in this country who loses as the nominee of their party. They become a losing for life, all right,” he said. “That’s it. It’s over.”

But speculation of a third run started swirling in December, when top donors to Romney said the 2012 nominee was considering another shot at the presidency. Romney shot down that speculation on Friday.

this story was updated at 12:50