NEW YORK ( TheStreet) -- David Einhorn, who heads the hedge fund firm Greenlight Capital, is making a big bet on the health-insurance industry and trimming technology holdings. Einhorn initiated new positions in Cigna ( CI) and Coventry Health ( CVH) during the second quarter, according to a securities filing released today. He also bought more of UnitedHealth ( UNH), Humana ( HUM), WellPoint ( WLP), and Aetna ( AET), adding between 1.6 million shares and 3.1 million shares of each to his portfolio. The bet on insurers may be related to the recent upholding of the so-called ObamaCare legislation by the Supreme Court. Over the next few years, several tens of millions of Americans will gain health insurance, boosting revenue and, some argue, profits. Still, the presidential election could change all that. Einhorn also added new positions in Virgin Media ( VMED) and Hess ( HES) during the second quarter. Big increases were made in Seagate ( STX) and General Motors ( GM), giving them the Nos. 2 and 3 spots in his portfolio, resprectively. Apple ( AAPL) is still Einhorn's top position in the fund, but he trimmed his holdings in the tech giant by 9,000 shares. Major reductions were taken in Best Buy ( BBY) and Compuware ( CPWR). Best Buy's stock declined 11% in the quarter as the company lost market share to online competitor Amazon ( AMZN). Einhorn exited before co-founder Richard Schulze offered to pay $24 to $26 per share for the company. Greenlight still owned about 1.2 million shares of both Best Buy and Compuware as of June 30. The total value of Einhorn's portfolio at the end of the quarter was $6.4 billion, which is up 15% from $5.5 billion at the end of March. Hedge funds that manage more than $100 million are required to disclose their equity holdings, options and convertible debt on a Form 13F filed to the Securities and Exchange Commission within 45 days of the end of a quarter. Funds aren't required to report short positions betting on declines. -- Written by Lindsey Bell in New York. >To follow the writer on Twitter, go to Lindsey Bell.