During today’s trading, it was made public that Third Point, the hedge fund run by activist investor Daniel Loeb, had raised it’s stake in Sotheby’s by more than half. Loeb now owns 5.7% of the auction house along with Marcato Capital which revealed a 6.6% stake at the end of July and Nelson Peltz’s Trian which bought 2.1m more shares it was revealed two weeks ago doubling Trian’s holdings and bringing that fund’s stake to around 6% as well.

Together, the three funds may own 18% of Sotheby’s or more (the filings are periodic and hedge funds buy and sell rapidly.)

Today’s news that Loeb had waded into Sotheby’s stock caused a significant spike in the shares.

Loeb’s Third Point Raises Stake in Sotheby’s (BID) to 5.74%; Seeks Talks w/ Management (StreetInsider)

BID Major Holders (Yahoo Finance)