It's pretty well established that the punishment for an agent's breach of the duty of loyalty to his principal is death.
At least in Russia at any rate
From Art Market Monitor:
Perhaps you’ve heard of this lawsuit where the dealers who bought a $10,000 painting and sold it for $80m are upset that the buyer was representing another buyer who sold it for almost $50m more?
Such is the trouble that Yves Bouvier’s dealings with Dmitry Rybolovlev have caused. Bouvier, acting in the interest of Rybolovlev, bought works of art that he then sold on to the Russian at huge markups. The whole scheme fell apart a few winters ago in St. Barth’s when an art advisor clued Rybolovlev in to the prices Bouvier was actually paying.
The New York Times has a story going into further detail. The dealers who sold Leonardo’s Salvator Mundi feel that Sotheby’s, which sourced a dozen of the works Bouvier sold to Rybolovlev, should have helped them get around Bouvier so they could make the higher sale to Rybolovlev themselves.
Here’s what the Times says is the dealer’s evidence:
Much of the speculation about Sotheby’s role in the sale of the Leonardo revolves around what its representative knew, or didn’t know, in 2013 when he took the “Salvator Mundi” to a Central Park apartment, where Mr. Bouvier and Mr. Rybolovlev inspected it.The meeting occurred six weeks before the sale to Mr. Bouvier and the flip to Mr. Rybolovlev. The meeting took place in a grand apartment, one of the most expensive in Manhattan, that is owned by a Rybolovlev family trust.In its court papers, Sotheby’s argues that its representative, Samuel Valette, its vice chairman for private sales worldwide, did not realize it was Mr. Rybolovlev’s family apartment or that he was inspecting the painting as a potential buyer.The meeting had been requested by Mr. Bouvier, the auction house said, and though Mr. Valette said that he recognized a third man in the room as having been associated with a previous sale to Mr. Bouvier, he said that he had not known his name.“It was not, however, until much later that Valette and Sotheby’s learned that this third man was Rybolovlev,” the papers state.One of the interesting wrinkles to this story is that Central Park West apartment. Rybolovlev bought it five years ago from Sandy Weil for $88m in a transaction that still marvels real estate experts. It seems that Rybolovlev’s credulous habits were not confined to his art purchases....MORE
