Jana Partners, the sometimes-activist fund run by Barry Rosenstein, took new stakes in Comcast Corp., Facebook Inc. and General Motors Co. during the fourth quarter while exiting Salesforce.com Inc. and Oracle Corp.

The New York-based hedge fund also took new positions in Syneos Health Inc., Envision Healthcare Corp. and WW Grainger Inc., according to a regulatory filing Wednesday. It said it exited DXC Technology Co., Altaba Inc. and UnitedHealth Group Inc.

Jana increased its position in Outback Steakhouse owner Bloomin’ Brands Inc. while selling down its stakes in Liberty Broadband Corp., EQT Corp. and DowDupont Inc.

The disclosure comes after Jana and the California State Teachers’ Retirement System sent a letter to the board of Apple Inc. in January, urging it to help parents find ways to restrict children’s access to mobile phones. The investors also want the company to study the effects of heavy usage on mental health, as part of new strategy by Jana to address social issues at companies.

This month, Jana also disclosed a new position in medical device manufacturer Boston Scientific Corp. It said in a January investor letter it had taken stakes in debt-laden drugmaker Teva Pharmaceutical Industries Ltd., Autodesk Inc. and PTC Inc., as well as Northrop Grumman Corp.

Jana said last month it would nominate Liz Claiborne Inc.’s former top executive William McComb to the board of Bloomin’ Brands, as part of its push for change at the owner of casual dining chain restaurants. Jana, along with two other investors, disclosed an 8.9 percent stake in the company in November.

Jana, which manages $4.6 billion in assets firmwide, has active positions in companies including Zimmer Biomet Holdings Inc., Blackhawk Network Holdings, Bristol-Myers Squibb Co. and Tiffany & Co.