Diamond Comics Distributors' newly-released sales figures for December confirm that the publisher claims a 33.4% majority in the dollar category and 36.12% in unit market share.
Amazing Spider-Man #700 Olivier Coipel variant cover
Rivals DC Comics ended the month in second with a 29.69% dollar share and a 34.84% unit share, Newsarama reports.
Amazing Spider-Man #700 was the bestselling comic of the month, one of six Marvel titles in the top 10 thanks to the success of the publisher's Marvel NOW! initiative.
DC's highest entry was Batman #15 in third place, one of four top-10 entries from DC.
The Walking Dead Volume 1: Days Gone Bye was the bestselling trade paperback of the month. Image Comics' zombie property dominated 2012's overall charts and helped the publisher to a 9.1% dollar share and 8.45% unit share.
Overall comic sales were up by 19% compared to December 2011, with overall sales seeing year-on-year gains of 15.74%.