Mayor Michael Bloomberg is no fan of the gun industry, but his representative on the board that oversees the pension fund for city schoolteachers voted against a proposal to drop investments in companies that sell firearms or ammunition.
Trustees of the $46.6 billion New York City Teachers' Retirement System approved the divestment last week in response to the school massacre in Newtown, Conn.
The only vote in opposition was cast by Bloomberg policy adviser Raymond Sarola.
He said in a statement that pension decisions should be based only on "what's best for pensioners.''
A Bloomberg spokesman says the mayor didn't tell Sarola how to vote and doesn't get involved in pension fund investment decisions.
The fund had a total of $13.5 million invested in five gun makers. Those included Smith & Wesson Holding Corp. and Sturm, Ruger & Co.
Bloomberg is the founder of Mayors Against Illegal Guns.