Jana Partners fourth quarter 2013 SEC 13F filing was published today, and there were some significant moves by fund manger Barry Rosenstein during the quarter. Rosenstein is part of an activist investor group trying to force Juniper Networks, Inc. (NYSE:JNPR) to cut costs and return more cash to shareholders.

Jana Partners added GM, Sirius and Sears, dropped Agrium

The latest 13F for Jana Partners shows that Rosenstein upped his bet on General Motors Company (NYSE:GM) from a mere 400,000 in the third quarter to just under 8 million in the fourth quarter. This figures does not include additional long-term warrants also purchased by Jana Partners. The fund also established new positions in both Sirius XM Holdings Inc. (NASDAQ:SIRI) (50 million shares) and a small position in Sears Holdings Corp (NASDAQ:SHLD) (99,917 shares).

Barry-Rosenstein Jana Partners

The fund also closed out its 10.8 million share position in Agrium Inc. (USA) (NYSE:AGU) over the quarter.

Juniper Networks investor activism

Jana Partners has established a 13,432,722-share position in Juniper Networks, Inc. (NYSE:JNPR) over the last few months. That means Jana has made a more than $300 million bet on Juniper. Rosenstein and colleagues are not just relying on the company’s fundamentals or improved sales. He has called on the company to intensify cost-cutting measures ad take steps to return cash to shareholders.

Jana Partners is joined by Elliott Management in its activist efforts with Juniper Networks, Inc. (NYSE:JNPR). Elliott is headed by Paul Singer, who also wants Juniper “to cut costs, streamline its product offerings and return money to shareholders”. Elliot has already disclosed a 6.2% stake in the network equipment giant. Both groups of activist investors have said that they hope Juniper’s new CEO (Shaygan Kheradpir) is looking to increase shareholder value in the near term.

It should be noted that SEC 13F filings only provide a moment-in-time snapshot of fund managers’ holdings, and are not necessarily up to date. The data in this 13F reflect Jana Partners’ portfolio as of Dec. 31. Jana and others may since have changed positions. Furthermore, not all securities must be reported on a 13F form. Managers sometimes hold derivatives or other investments which do not have to be disclosed on a 13F.