This AP story says Senator Bernie Sanders (I-Vermont) will decide by March 2015 whether to run for President in 2016. It also says he will decide whether to run for the Democratic nomination, or as an independent.
Presumably Senator Sanders knows that if he runs as an independent he can’t receive primary season matching funds from the federal government, but he can receive them if he says he is seeking the nomination of any party, no matter how small. Also, Sanders probably knows that if he ran as an independent, he would face the challenge of getting on the ballot in all 50 states, whereas the Green Party is currently ballot-qualified in twenty states, including five of the nation’s seven most populous states. Thanks to PoliticalWire for the link.