Of course he does.
Check this out:

Outgoing New York City Mayor Michael Bloomberg hailed 2013 as a successful year for gun control despite no action from Congress, citing several state laws.

Bloomberg, who founded Mayors Against Illegal Guns in 2006, co-wrote an op-ed in Politico Magazine with Shannon Watts, who founded Moms Demanding Action after the massacre at Sandy Hook Elementary School in Newtown, Conn., just over a year ago. The op-ed announced the merger of the two groups

“To get Congress to listen, we must unite supporters from every walk of life. And that is why our two organizations are merging to create a nationwide movement of Americans – mayors, moms, survivors of gun violence, law-enforcement leaders and gun owners,” they wrote.