Bill Gates Owns One Of Leonardo Da Vinci’s Manuscripts. Here’s How Much It’s Worth.

For more than three decades Forbes reporters have tracked the fortunes of the richest people on the planet: putting dollar figures to their business empires, their one-of-a-kind art, their private islands and more. 

Now, in a new series called “Priceless,” we’re taking you behind the scenes to show you how we determine the value of the most unique assets owned by members of The Forbes 400. 

How does Forbes estimate the value of a one-of-a-kind piece of art? In this episode, we look at the only Leonardo da Vinci manuscript that is still in private hands after more than five centuries: the Codex Leicester. Back in 1994 the estate of original Forbes 400 member Armand Hammer put the Codex up for sale at Christie’s. The new buyer? None other than the country’s richest man that year: 39-year-old Microsoft cofounder Bill Gates. 

At the time, Gates paid $30.8 million for it. But what is it worth today? To figure this out, we dove into the world of rare books, manuscripts and Old Masters works. To help us with our estimate, we interviewed experts including Old Masters dealer Robert Simon, who has a connection not only to the Codex Leicester, but also to the Salvator Mundi, another da Vinci work that is synonymous with wealth and power. 

Watch the rest of the Priceless series—where we explain how we estimate the values of a Thoroughbred horse farm and a billionaire-owned water bank.