After writing a letter Friday to Sotheby's, chiding it for enacting a "poison pill," hedge-fund titan Dan Loeb spoke exclusively to CNBC and said he expects action.
Loeb wants the company to replace CEO William Ruprecht and add new board members, including himself. He told CNBC there's "no good reason" he shouldn't be added to the board, given that he's the largest shareholder and has a track record of creating value for shareholders.
"It would be a shame if we had to wait until proxy season to do anything," he added.
"It's incumbent on the board to either say it's satisfied with the CEO's performance or set out a road map as to how they're going to improve performance, improve cost issues and its deteriorating competitive position," Loeb said.
He also commented on the high-flying art market, saying, "It's just getting started" and "prices will go up from here."
—By CNBC's Scott Wapner. Follow him on Twitter