Collector Charles Cahn has filed a lawsuit against Sotheby’s in New York Supreme Court, alleging the auction house reneged on a buy-back agreement made in 2016 regarding a Modigliani portrait he purchased in 2003. Cahn paid $1.55 million for *Portrait de Leopold Zborowski* at a Sotheby’s Impressionist and modern sale, and later agreed to consign the work back to Sotheby’s if he sold it within 15 years, with the house guaranteeing the greater of the original price plus 2.5% annual compound interest or the future sale price, and waiving vendor fees. However, Cahn claims that in April 2016, Sotheby’s own appraisal questioned the painting’s authenticity, stating it failed certain criteria and would have no sale value in the international art market. Despite Cahn’s letters in June and September 2024, Sotheby’s has not responded, leading to the breach-of-contract claim seeking at least $2.7 million in damages.
The case highlights persistent authenticity disputes in the Modigliani market, which has long been plagued by conflicting expertise and a contested catalogue raisonné. The lawsuit underscores the risks collectors face when relying on auction-house guarantees tied to works whose provenance or attribution may later be challenged. It also raises questions about the responsibilities of major auction houses in upholding contractual obligations, especially when the value of a high-profile artist’s work—like Modigliani, whose *Nu couché* sold for $170.4 million in 2015—can swing dramatically based on authentication rulings.