Mavs' Cooper Flagg Opens Trading Card Company in Maine

Cooper Flagg's 1-of-1 rookie trading card - completed with his autograph and the patch from his NBA debut with the Dallas Mavericks - was a hot topic in the world of collecting this summer.

It was pulled by Jason Williams, a 55-year-old collector in South Carolina, and after initially mulling over what to do with the memorabilia that had already received seven-figure offers, it was sent to auction.

As it turns out, Flagg is a card collector himself. That might explain his nerves as he signed his debut patch card at Fanatics Fest earlier this summer, knowing the significance this piece hold on the market.

Flagg just opened his own card shop, Flagg Trading Co., in Bangor, Maine last week.

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The reigning Rookie of the Year said he first had the idea with his cousin, Tyler, and as the shop took shape, it drew a crowd of hundreds - many camping overnight - ahead of its ribbon-cutting ceremony.

"I think it started when I was starting to sign more cards for fanatics, and the local hobby kind of grew for me from there," Flagg said of the hobby, via FOX 22 in Bangor. "Tyler was also into the hobby. He was into it when he was young and then picked it back up when he got older. So we both kind of just had a love for the hobby, had mutual interest, and decided this is what we wanted to do."

The Newport, Maine native said the decision to open a shop in his home region was intentional due to the difficulties of collecting in an area without major shops like the big cities.

"I feel like there aren't a ton of places like this. I also feel like we can have pretty good outreach and distribution of product, and fulfill the needs of a lot of people," Flagg said. "There aren't a lot of places like this. We will have a pretty good outreach and distribution. We will have a lot of product and will be able to fulfill the needs of a lot of people. I felt that struggle before [as a collector]. Not being able to find certain things. You go to Walmarts and certain stores like that and stuff flies off the shelves.

"This will be a place where people can go and know they will be able to find some good stuff."

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Flagg's rookie card will headline Fanatics Collect's September Premier Auction, which runs from Sept. 10 through Sept. 24. It has already received a PSA Gem Mint 10 grade, strengthening its status as one of the most significant basketball cards in the hobby.

The offers Williams rejected are particularly striking. Goldin Auctions founder Ken Goldin offered a $1.5 million cash advance before the card reached the auction block. The Mavericks assembled an experience package valued between $800,000 and $1.2 million that included decades of season tickets and access to Flagg himself. Most notably, the marketplace Alt opened what it called a Debut Bounty Auction. Bidding reached $3 million, or $3.6 million with the buyer's premium, on the condition that Williams consign the card there. He declined every offer.

Williams remained quiet about his plans for several weeks. Shortly after pulling the card, he told ESPN, "It's in a safe place for right now. I'm just sort of trying to lay low."

The market will now get its answer. Every valuation so far has been speculative, ranging from Sports Cards Investor founder Geoff Wilson's early estimate of $1.5 million to projections between $3 million and $5 million. Only a completed auction can establish the card's actual value.

The closest precedent comes from another sport. Paul Skenes' 1-of-1 MLB Rookie Debut Patch Autograph sold through Fanatics Collect for $1.11 million in March 2025, making it one of the most expensive baseball cards ever sold. That card followed a similar path, including a franchise bounty package from the Pirates that the family ultimately declined in favor of an auction.

It remains uncertain whether Flagg's card will match or exceed that price. Baseball and basketball collector markets behave differently, so direct comparisons are imperfect. However, Flagg's previous card record is $366,000, which was set at a March auction. This card is expected to surpass that figure by a wide margin.

The card's value comes partly from the memorabilia embedded in it. The patch was cut from the jersey Flagg wore during the first half of his NBA debut on Oct. 22, 2025. That jersey sold for $1 million at NBA Auctions in February. Topps later had Flagg sign the card at Fanatics Fest in July, where he admitted that he felt a little nervous before signing it. Flagg wore three debut patches that night, and the other two were intentionally destroyed to ensure that this card remained unique.

The auction opens Sept. 10 and closes two weeks later. When it ends, the hobby will finally know what a Cooper Flagg debut patch is actually worth.