With six weeks having passed since the end of Q1 in March, hedge funds have now submitted 13-F reports to the SEC. These filings detail net changes in holdings for a variety of different types of positions, and analysts are now looking to the biggest names in the money manager field to get a sense of how those investors used their money in the first few months of 2017. Barry Rosenstein, the leader of JANA Partners, has long been seen as a leader in the hedge fund world. JANA's 13-F shows a number of significant changes and a relatively high degree of turnover in portfolio. Here are some of the highlights of the first quarter for Rosenstein's fund.

New Positions in Dow Chemical, Hewlett Packard, Formula One, Tiffany, and Whole Foods

Rosenstein took up new positions in about two dozen companies in the first three months of this year. Some of the new stakes were relatively small. A new position of 50,000 shares of Ardagh Group (ARD), for instance, doesn't make much of a splash in Rosenstein's portfolio. Other new buys, however, were more significant. Among the top purchases in terms of share volume were new positions in Dow Chemical (DOW), with more than 3.5 million shares. Rosenstein also bought up a significant stake in Hewlett Packard Enterprise (HPE), amassing a collection of 4.4 million shares. JANA bought 4.1 million shares of Formula One (FWONK) during this period, as well as 5.6 million shares of Tiffany & Co. (TIF), with another 73,600 shares in call options. Further, JANA bought up 14.2 million shares of Whole Foods Market (WFM) and close to 3 million shares in call options.

Increased And Lowered Stakes

Like most hedge fund managers, Rosenstein also adjusted his positions that already existed, raising some and lowering others. He added considerably to Aetna Inc. (AET) during this period, climbing from just under 900,000 shares to roughly 1.5 million shares. He nearly doubled his holding of Cognizant Technology Solutions (CTSH) to 2.6 million shares. Zayo Group (ZAYO) also more than doubled, from just over 1 milllion shares to 2.4 million shares.

Rosenstein lowered holdings of Bristol-Myers Squibb (BMY) from 3.8 million to 716,000 shares. He also trimmed ConAgra Foods Inc. (CAG) from 17.8 million to 6.4 million shares. There were a number of other lowered stakes as well, none of which were as significant.

Finally, Rosenstein liquidated 20 positions in the first quarter. Among others, he eliminated positions in Dell Technologies Inc. (DVMT), Lamb Weston (LW), and Time (TIME). A number of the liquidated positions were in the biotech area, including Puma Biotechnology Inc. (PBYI), Neurocrine Biosciences, Inc. (NBIX), and Incyte Genomics, Inc. (INCY).