Major League Baseball and the Major League Baseball Players Association have agreed to a new exclusive trading card deal with sports apparel and collectible retailer Fanatics Inc., according to people familiar with the matter.

The move will end the longstanding dominance of Topps Co. in baseball, while Fanatics gains a crucial foothold in the booming market for trading cards. Fanatics has also signed other sports properties to exclusive licenses, though they haven’t yet been revealed, said one of the people, who asked not to be identified because the matter is private.

Representatives for MLB and Topps didn’t immediately respond to requests for comment. Fanatics and the MLBPA declined to comment.

Fanatics is undergoing a reorganization under founder Michael Rubin, who has taken over as chief executive officer, with plans to get into several new sectors beyond sports merchandise, including online gambling, ticketing and media. The company has applied for a mobile sports betting license in New York as the state opens to the industry.

Sports collectibles have become a popular alternative asset class, giving companies in the burgeoning market a lift. Topps is going public through a deal with a special purpose acquisition company, while rival Panini SpA has attracted interest as well. Memorabilia have gone for record prices, including an extremely rare 1952 Topps Mickey Mantle card that was auctioned for $5.2 million in January.

Fanatics was valued at $18 billion after raising $325 million in fresh funding earlier this month. As part of the arrangement, MLB and the MLBPA will have equity stakes in Fanatics, said the people. 

The MLB deal was reported earlier by the Wall Street Journal.

—Bloomberg News