Although he isn't playing in this year's NBA Finals, Golden State Warriors star Stephen Curry is still setting records. 

On Tuesday, one of the guard's rookie cards sold for $5.9 million. The 2009 National Treasures 1/1 Rookie Logoman Autograph surpassed the record $5.2 million purchase of a 2003 Exquisite LeBron James Patch Auto in April. Previously, the James card had been tied with a a 1952 Topps Mickey Mantle card for the highest sale. 

Investment firm Alt acquired the majority 51 percent stake of the rarest Curry card in existence. The company bills itself as an "alternative asset platform that makes investing in trading cards as easy as investing in stocks." Now they control one of the most valuable cards ever sold.

"Steph is a generational player," Alt founder Leore Avidar said (h/t Markets Insider). "Our data shows that Steph's cards have increased 35% in value YTD — compare that to the S&P and you can see the outsized return potential." He continues, "We believe this card's upside is tremendous and represents the best of the best of the entire sports card market. We're anchoring Alt Fund II to this purchase and have built a thesis with this asset at its core."

Alt said the card will anchor its second investment fund, Alt Fund II.