Eton Park Capital Management’s latest regulatory filing shows that it stepped into the Sothebys (NYSE:BID) debate during the third quarter. The company also exited 21st Century Fox and News Corp (NASDAQ:NWSA). In all, the firm bought into 12 new stocks and added to its position in five others. It also exited 17 stocks and cut its holdings in 10 others.

The firm’s portfolio appears to have declined in value during the third quarter from $5.2 billion at the end of the previous quarter to $4.5 billion at the end of September.

Eton Park’s buys and increases

Perhaps one of Eton Park’s most notable purchases during the September quarter was Sothebys (NYSE:BID)’s of which the firm bought almost 2 million shares. Activist investor Dan Loeb has been targeting the auction company for the last few months.

Eton Park also bought 6.5 million call options of 21st Century Fox (NYSE:FOXAV) and 11.5 million shares of the company, making it one of its top five holdings with more than 8% of its portfolio in the company. Another notable new stock for Eton Park was Family Dollar Stores, Inc. (NYSE:FDO).

The firm’s major position increases during the September quarter included Moody’s Corporation (NYSE:MCO), CBS Corporation (NYSE:CBS) and Spirit AeroSystems Holdings, Inc. (NYSE:SPR).

Eton Park’s sells and reductions

The fund exited News Corp (NASDAQ:NWSA), selling 17 million shares of that company. Eton Park also sold all 13 million of its shares of Sprint Nextel Corporation (NYSE:S) and all of its 3 million shares of Clearwire Corporation (NASDAQ:CLWR), which of course was acquired by Sprint in July.

Major reductions during the September quarter included LIBERTY GLOBAL PLC (NASDAQ:LBTYA), although the company still remained one of the firm’s top five holdings. Eton Park also cut its position in Dollar General Corp. (NYSE:DG), Dollar Tree, Inc. (NASDAQ:DLTR), Yandex NV (NASDAQ:YNDX) and Baidu Inc (ADR) (NASDAQ:BIDU). It also sold some of its shares of eBay Inc (NASDAQ:EBAY), although the company still remains in the firm’s top five positions.