MSNBC reported that Sen. Sanders is leaning towards running for the Democratic nomination in 2016:

Sen. Bernie Sanders is only days away from making a decision on a 2016 run, and leaning towards yes, according to his top strategist.

“I think we’re coming to the critical moment of truth here. He’s now spent enough time traveling around the country talking to people and feels there is genuinely a large audience of people who are with him,” veteran Democratic strategist Tad Devine, who is advising Sanders, told msnbc.

A formal announcement of his candidacy is expected to occur later in May.

http://www.politicususa.com/2015/04/25/bernie-sanders-run-president.html (Emphasis in original)