A rare copy of Superman's 1938 comic-book debut sold at auction for almost $1 million.

In a statement, Dallas-based Heritage Auctions said the copy of Action Comics No. 1, bearing a cover price of 10 cents, sold Thursday for $956,000. It is one of about 100 copies of the edition known to exist.

Certified Guaranty Co. graded the copy 5.5 out of a possible 10. It had been expected to sell for about $750,000.

Heritage says the copy came from the collection of an unidentified East Coast comic book fan who had bought it in the 1990s for $26,000.

Spokesman Eric Bradley says the winning bidder also did not wish to be identified.