Marvel has put a lot of effort into launching its new Guardians of Galaxy comic book series including producing a .1 issue that sold over 80,000 copies and assigning top talent  (writer Brian Michael Bendis and artist Steve McNiven) to the project.  With a Guardians of the Galaxy movie in the early stages of production, Marvel and Disney have a lot riding on this property, and the publisher should be pleased that according to ICv2’s calculation Diamond Comic Distributors shipped 211,312 copies of the official #1 issue to comic shops in North America making Guardians #1 the bestselling comic book in March.
Bendis also wrote the #2 book in March, the Age of Ultron #1, which features art by Bryan Hitch and debuted with a very healthy North American circulation of nearly 175,000 copies.  The Age of Ultron, a 10-issue crossover series that Marvel is hoping will energize the company’s sales over the next five months, appears to be off to a very strong start thanks in part to slick foil cover and a savvy marketing campaign.  An Age of Ultron side issue of Superior Spider-Man came in at #12, which is another good sign for Marvel, though the task for the publisher now becomes maintaining sales momentum throughout the full 10-issue maxiseries.
Another #1 issue from Marvel, Wolverine #1 landed at number 4, giving Marvel 3 out of the top four spots, all of which were secured by #1 issues.  In a month in which Marvel exploded to a huge 13-point marketshare lead (see "Comic Market Up 22+% in March"), the "House of Ideas" managed to land 7 out of the top ten spots and 14 out of the top twenty.
DC’s top title was Batman #18, which dealt with the aftermath of the popular "Death of a Family" storyline, was once again the top-selling DC book.  Three other Batman titles that made the top 25, Detective Comics, Batman and Robin, and Batman Incorporated, also dealt with the "Death of Robin" aftermath.  The four Bat books were joined the top 25 by Justice League #18 (at #6), Justice League of America #2 (at #9), and Action Comics #18, the final Grant Morrison issue.
The only non-Marvel and DC title in the top 25 was Image Comics’ The Walking Dead #108, which gained almost four thousand copies in circulation over the previous issue providing more proof of the influence of the hugely popular The Walking Dead TV series, which just concluded its third season with the a finale that became the most-watched drama series in basic cable history.
Only four other titles in the top 25 posted increases in March, while 18 suffered declines in circulation.
On the graphic novel side DC’s Batman compilations took the top two spots with the new hardcover edition Batman: City of Owls at #1 followed by the new trade paperback edition of the first Batman "New 52" collection, Batman: Court of Owls.  But Marvel also did well on the graphic novel charts, claiming four of the top ten spots led by the Hawkeye: My Life as a Weapon trade written by Matt Fraction.  Other Marvel titles include a trade paperback edition the $75 hardcover that includes the Avengers vs. X-Men event as well as trade paperback edition of the Kick-Ass 2 hardcover, as well as the Kick-Ass 2 Prelude Hit-Girl Premium Hardcover.
Image Comics also placed two titles in the graphic novel top ten, though neither of these books debuted in March. Volume #1 of Robert Kirkman’s The Walking Dead has been a near constant presence high on the monthly graphic novel list since the debut of the AMC TV adaptation, and Brian K. Vaughan and Fiona Staples’ Saga Vol. 1 has become a fixture on this list since it debuted in October of 2012, both because it is one of the hottest new titles in the direct market and because Image has wisely kept the price of the inaugural volume in the series at a very reasonable $9.95.
The top manga title on the list was Dark Horse Comics’ Blade of the Immortal, which came in at #43.  Dark Horse also had the #4 book in March with the fourth volume in Gene Luen Yang’s series of graphic novels based on the Avatar: The Last Airbender animated series.
Here are ICv2’s estimates of the North American sales of the top 25 comics sold through Diamond Comic Distributors in March of 2013:
211,312           Guardians of the Galaxy #1
174,952           Age of Ultron #1
137,893           Batman #18
117,669           Wolverine #1
109,383           Age of Ultron #2
102,494           Justice League #18
100,347           Age of Ultron #3
 94,224           Superior Spider-Man #5
 91,734           Justice League of America #2
 90,980           All New X-Men #8
 86,614           Superior Spider-Man #6
 85,807           Superior Spider-Man #6 Age of Ultron
 85,775           Uncanny X-Men #3
 84,332           Uncanny Avengers #5
 82,691           Avengers #8
 81,695           All New X-Men #9
 78.278           Avengers #7
 76,237           Detective Comics #18
 69,801           Green Lantern #18
 69,614           Batman and Robin #18
 67,423           The Walking Dead #108
 65,150           New Avengers #4
 64,067           Batman Incorporated #9
 61,879           Action Comics #18
 57,095           Deadpool #6

For an analysis of the dollar trends in March, see "Comic Market Up 22+% in March."

For our estimates of actual sales by Diamond U.S. from comic specialty stores on comic books shipped during March, see "Top 300 Comics Actual--March 2013."

For our estimates of actual sales by Diamond U.S. from comic specialty stores on graphic novels shipped during March, see "Top 300 Graphic Novels Actual--March 2013."

For our estimates of actual sales by Diamond U.S. from comic specialty stores on comic books shipped during February, see "Top 300 Comics Actual--February 2013."

For our estimates of actual sales by Diamond U.S. from comic specialty stores on graphic novels shipped during February, see "Top 300 Graphic Novels Actual--February 2013."

For an overview and analysis of the best-selling comics and graphic novels in February, see "52 Variants Garner Million Dollar Book."  For an analysis of the dollar trends in February, see "Comic Market Continues Growth."

For our index to our reports on the top comic and graphic novel preorders for January 2000 through March 2013, see "ICv2's Top 300 Comics and Top 300 GNs Index."