Michael Bloomberg spent $12 million on gun control advertising this year, Gun control groups outspend gun owner groups by 7.4 to 1

Gun control groups out spent gun owner groups by 7.4-to-1.  The vast majority of spending has come from Michael Bloomberg's Mayors Against Illegal Guns.  From Ad Age:

In the year after the massacre at Sandy Hook Elementary School in Newtown, Conn., gun-control groups spent $14.1 million on TV advertising. According to Kantar Media's CMAG, that gave such groups a seven to one advantage over gun-rights organizations, which only spent $1.9 million. . . . 

Michael Bloomberg, the outgoing New York City mayor and a billionaire, was responsible for most of the spending on the gun-control side. Founder of Mayors Against Gun Violence, Mr. Bloomberg budgeted $12 million for an ad campaign this year. The effort was kicked off with celebrity-heavy ads demanding a plan but became more targeted as the year went on, even reaching out to "responsible gun owners." . . .

See my related piece at Fox News. As an additional point, note that Ad Age only manages to have links to gun control ads.  Not one ad on the other side is shown.