Ken Griffin is back in the news this autumn. The bon vivant billionaire investor took to a Sotheby’s auction this month where he was last person standing during a short but spirited bidding war.

The lot: a first printing copy of the final draft of the Constitution of the United States. Auction estimates topped out at $20 million. But Griffin had to make a rather more sizeable commitment to add this particular piece of living history to his collection. By the time the dust had settled and the gavel had sounded its final wallop, he’d agreed to fork over $43.173 million for it. The document was on the auction block in 1988; it fetched $165,000 back then.

This particular example is one of a run printed for the delegates of the Constitutional Convention. A final draft, it is one of five hundred original copies, of which only 13 are known to have survived to the present day. Eleven of the thirteen are held by institutions.

Griffin intends to loan the document to the Crystal Bridges Museum of American Art, a free museum in Bentonville, Arkansas, which was built by Alice Walton. Walmart’s headquarters are located in the city as well.

Griffin’s flair for judicious investments usually involves the type of curiosity-inducing spending that ends up in the news. His portfolio includes a $100 million-plus compound on South Florida’s Star Island, a $100 million-plus Basquiat, the $100 million-plus former Hamptons retreat of Calvin Klein, a $350 million-plus Palm Beach compound, a record-breaking $238 million residential purchase at 220 Central Park South in Manhattan, and an abstract expressionist set: a de Kooning and a Pollock, which ran the Citadel founder $500 million.

Griffin’s net worth is around $21 billion.