A copy of Action Comics No. 1 flew off the auction block Thursday, selling for $3.18 million, the fourth-largest sum ever for a comic book.

1938’s Action Comics No. 1 is considered one of the most important comics of all time. Within its pages, Jerry Siegel and Joe Shuster introduce the world to Superman, the hero who launched the superhero genre in earnest. This particular copy of the DC Comics title is called “the Rocket Copy” because the cover features a rocket stamp put there by the 13-year-old who purchased the issue from a newsstand in 1938. Heritage Auctions handled the sale.

Thursday’s Rocket Copy sale stands behind an issue of Amazing Fantasy No. 15, the first appearance of Spider-Man, that sold for $3.6 million in September 2021, and two other copies of Action Comics No. 1. The Rocket Copy is graded at a condition of 6.0 by the CGC, a service that authenticates the condition of comics. The other Action Comics issues that have sold for more were an 8.5 that went for $3.25 million in April 2021, and a 9.0 that sold for $3.2 million in August 2014.

This was the first time the Rocket Copy of Action Comics No. 1 has been sold. Goldin, a collectibles marketplace, purchased the copy on behalf of a private buyer. “It was fun bidding and winning a $3 mil + item. I know it’s going to a great home!” Goldin’s Ken Goldin tweeted after winning the auction.

The purchase comes as the comic book collecting space has heated up during the pandemic, with original art and comics routinely fetching record prices.

Updated to clarify that Goldin purchased the copy of Action Comics No. 1 on behalf of a private buyer.