If New York Mayor Micheal Bloomberg decides to run as an Independent who will it affect more Democrats or Republicans?

I would say it hurts the Democrats and helps the Republicans. Bloomberg technically served as a Republican in New York City, but no "real" Republican can win in New York (just look at their Senators and Governor). His ideology is clearly closer to that of Hillary Clinton than of a Ted Cruz, Marco Rubio, or Jeb Bush. He would therefore pull more votes away from Clinton than he would from a Republican candidate in my opinion.

I'd have to say he'll hurt the Democrats more. They are in greater need of a viable candidate and Bloomberg's progressive positions, especially on gun control, won't attract many Republicans. The real question is how the Independents will lean. I suspect they may split. Those who are disgusted with the GOP candidates, especially Trump, and might have stayed at home, will probably turn out for Bloomberg. Those who are tired of politicians and want an outlier will go for Trump if he is the GOP nominee. If a politician takes the GOP nomination, say Cruz, then the Republicans will stay at home thinking that Bloomberg is acceptable but not excited enough to go vote for him.

It will spit the Democrat vote! YAY!