A mint condition Mickey Mantle baseball card became the most valuable piece of sports memorabilia to be sold at auction, notching $12.6 million early Sunday morning.

The card, issued by the collectible company Topps in 1952, features Mantle, the most powerful switch-hitter in baseball history. It would have been sold at the time in a wax-wrapped pack that cost either a penny or a nickel, said Chris Ivy, the director of sports auctions at Heritage Auctions, which sold the item.

Now, the card has become the first sports item to be sold at auction for eight figures. “We always knew this card would shatter records and expectations,” Mr. Ivy said in a statement. “But that doesn’t make it any less of a thrill.”

The card surpassed the record of $9.3 million achieved earlier this year by the jersey worn by Diego Maradona when he scored the goal known as the “Hand of God” in the 1986 World Cup.

The sale of the baseball card marks a new high for the sports collectible market, one that has been booming in recent years, especially since the beginning of the coronavirus pandemic in 2020. Baseball cards can carry a sense of nostalgia.

“People are starting to look at these collectibles as legitimate alternative assets,” Mr. Ivy said by phone.

Michael Osacky, the lead appraiser for Professional Sports Authenticator, the largest third-party grader of sports collectibles, started working as an appraiser in 2012. Before 2020, he said there was little interest from hedge fund managers or private equity firms. But in the last two years, he said, he has been swamped with inquiries from people who see the collectibles as an investment.

He added, “All of a sudden people are like, ‘Wow, this stuff could be art.’”

According to Heritage Auctions, the Mantle card was graded a 9.5 out of 10 by Sportscard Guaranty Corporation, which authenticates and grades trading cards.

“It’s almost perfectly centered top to bottom and left to right. It’s got four sharp corners. The color is beautiful.” Mr. Ivy added, “The fact that it remained in this condition for 70 years, prior to being graded, is truly a miracle.”

According to Heritage Auctions, the card was purchased by an anonymous baseball fan from Rye, N.Y., from Anthony Giordano, the president of a recycling and solid waste business in New Jersey.

By phone, Mr. Giordano, 75, said that he had purchased the card in 1991 at a Father’s Day baseball card show he was attending with his son at Madison Square Garden. He paid $50,000, at the time a record for that specific card.

Mr. Giordano said that he and his son had been looking for a 1952 Mantle card, but until that moment, nothing had really seemed right. “When we saw the price on this card, we knew it had to be something special.”