'Quiet wealth' takes on new meaning with super-private deals for mansions, art and classic cars

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The rich have taken "quiet wealth" to a new level, turning to private purchases of mansions, art and classic cars designed to avoid attention, according to experts.

Auction companies and luxury real estate brokers say wealthy buyers and sellers are increasingly turning to private sales and off-market listings to avoid social media and prying eyes. While public auction sales are declining in the art world, private sales — done behind closed doors between discreet buyers and sellers — are growing.

Last year, while combined public auction sales for Sotheby's, Christie's and Phillips fell by 19%, private sales increased by 4% at Sotheby's and 5% at Christie's, totaling $2.4 billion across the two auction houses. CNBC reported in February that Christie's had sold a Mark Rothko painting for over $100 million to hedge-fund billionaire Ken Griffin, even as public auctions continued to decline.

Classic cars are also seeing a shift to private sales, especially with the most expensive and rare models. RM Sotheby's, the classic-car auction company, has sold trophy Ferraris, Porsches and other trophy cars by public auction for more than 30 years. But its newly formed RM Sotheby's private sales division has seen its sales more than quadruple over the past four years, according to Shelby Myers, global head of private sales for RM Sotheby's.

Private sales, where cars are discreetly brokered between buyer and seller without an auction or public price, now account for nearly a third of revenue, he said.

"We've definitely seen a