ST. JOSEPH, Mo. — Chiefs quarterback Patrick Mahomes is used to setting records on the football field, but even he seemed surprised about a new record he now holds.

An autographed Mahomes rookie card sold for a record $4.3 million in a private sale, according to the PWCC Marketplace.

“That’s a lot of money, I’ll say that,” Mahomes said when asked about the card at Chiefs training camp. “I knew that it was going up for auction, I found out, but for the go for that much and it shows that that business has been growing.”

Mahomes also tweeted after seeing the astronomical sale price.

Mahomes said he remembers collecting trading cards with his dad as a kid.

“It’s really is a cool thing to see, especially when it has your name on it,” Mahomes said. “I don’t know that I’d have gone all the way up there, but I mean, I don’t know the ins-and-outs of it like those dudes do and they definitely use it as an investment. I’m sure they’ll try to sell it later for more money.”

The previous record was a Tom Brady rookie card that sold for $3.1 million in March.