Miety Heiden, Sotheby’s senior vice president and head of contemporary private sales for North America, is leaving the company. The house confirmed Heiden’s departure in an email to artnet News this morning.

Numerous departures of veteran staffers have come on the heels of the house’s acquisition in January of the consulting firm Art Agency, Partners (AAP). Sotheby’s paid some $50 million—plus performance incentive costs of up to $35 million—for the firm, founded in 2014 by ex-Christie’s contemporary head Amy Cappellazzo and high-powered art advisor Allan Schwartzman. Investment banker Adam Chinn later joined AAP.

The publicly traded company’s stock (BID) has fallen 40 percent over the last year, from $41.73 to $25.18 per share, but today it was up to $25.91, following news that the auction house hired Michael Goss as CFO.

Heiden had worked for the auctioneer since 1997. In recent years, both Sotheby’s and Christie’s have increasingly focused on private sales, which are generally more lucrative, since they avoid the hefty costs of staging public auctions and publishing auction catalogues.

She contributed to business development and managed client relationships for the New York and Hong Kong contemporary art evening and day sales, as well as focusing on emerging markets and drumming up business on the West Coast. She was also a consultant to the Chinese contemporary art department, and was previously head of the modern and contemporary art department in Amsterdam.

On Monday, Henry Wyndham, chairman of Sotheby’s Europe, left after some twenty years. That announcement, in turn, followed by one day the news of the departure of David Norman, vice chairman of Sotheby’s Americas and co-chairman of Impressionist and modern art worldwide, and Alex Rotter, global co-head of the contemporary art department. They had worked for the auctioneer 31 years and 15 years, respectively.

Melanie Clore, the house’s European chairman and worldwide co-chairman of Impressionist and modern art, announced her departure in February. She had joined Sotheby’s in 1981.

In November, the company offered its staff buyouts, indicating in an email sent to staff that the company would have to resort to layoffs if a not enough employees chose the house’s enticements to leave. Departures since then have included longtime executive Mitchell Zuckerman; Polly Sartori, who headed up 19th-century European art in New York; and Aileen Agopian, Anthony Grant, and Scott Nussbaum, all of whom worked in the contemporary art department in New York.

The house sustained a loss—initially estimated at$12 million—on the November 2015 sale of the collection of its late former chairman, A. Alfred Taubman. Sotheby’s had taken the unusual step of offering Taubman’s heirs a jaw-dropping $500 million guarantee on Taubman’s estate, which included major artists such as Amedeo Modigliani, Pablo Picasso, Willem de Kooning, and Mark Rothko.

In March of last year, the firm appointed former Madison Square Garden CEO Tad Smith its new CEO after a prolonged battle with activist investor Daniel Loeb, who was lobbying for major changes in the way Sotheby’s does business. The spat ended in Loeb’s joining the board along with former investment banker Olivier Reza and turnaround specialist Harry Wilson. Loeb nominated both Reza and Wilson.