This is one for the art law nerds. But it’s a good one. Lisa de Kooning inherited a lot of her father’s art (57 paintings, 83 sculptures and 51 drawings.) She died in 2013. At that time, her lawyers got Christie’s to value the trove at $231m. Separately, the lawyers got two different academic opinions on an appropriate blockage discount (the value of the works sold at all at once now—to a dealer or some other sort of speculator—instead of putting the works on the market slowly over time.

The number they came up with was 60% off for the flat art and 85% for the maestro’s sculptures. But the IRS had a different view. Their panel of experts essentially said that de Kooning was a no-risk artist. The value of his work could only go up over time (that’s some confidence in art history.) Here’s what happened next, according to Law 360, and what the lawsuit her estate has filed to sort out:

The IRS’ art appraisal division largely rejected the submissions, finding that no blockage discount should apply to the paintings given that it expected significant appreciation in the value of the works, and only a 50 percent discount for sculptures valued at more than $100,000, the petition said. After applying those discounts, the IRS’ statement of value pegged the artwork at $255.2 million.

In filing its return for the year 2013, the estate submitted additional information to challenge the agency’s statement of value, ultimately reporting that the artwork has an after-discount value of $100 million. In response, the IRS increased the pre-discount value of the artwork nearly $60 million above what it had previously determined in the statement of value and slashed its original 50 percent discount for sculptures to zero, according to the petition.

De Kooning Estate Battles $92M Tax Bill Over His Artwork  (Law360)