You may know who David Tepper is. In case you don't, he's a hedge fund manager. He made $4 Billion last year and currently ranks as the 258th richest person in the world. Carnegie Mellon’s named their business school after him. On September 24th he said the stock market is going to go up because of the second round of QE. Now we know which stocks he was buying at the time. David Tepper's Appaloosa Management had been investing in technology (specifically semiconductors), paper products companies and healthcare companies. The Tech Stocks Tepper Bought: Hewlett-Packard (HPQ)  - 3.7 Million shares Cisco (CSCO) - 6 Million shares Semiconductor ETF (SMH) - 1.7 Million shares Applied Materials (AMAT) - 3.8 Million shares He also bought smaller quantities of KLA-Tencor Corp (KLAC), Lam Research (LRCX), Texas Instruments Inc (TXN), Intel Corp (INTC), Analog Devices Inc (ADI), Broadcom Corp (BRCM), and Xilinx Inc (XLNX). Warren Buffett's Berkshire also initiated a new position in Intel in 2011. The Healthcare Companies Tepper Bought: Medtronic (MDT) - 1.4 Million shares UnitedHealth (UNH) - 1.2 Million shares Wellpoint (WLP) - $34 Million worth Other healthcare stocks in his buying spree include Covidien (COV), Becton Dickinson (BDX), and Cigna (CI). In paper products, Tepper bought shares of International Paper (IP) and Temple-Inland (TIN). It's obvious that David Tepper isn’t a stock picker. He's more of a sector investor. He also seems opportunistic about his Hewlett-Packard investment. He was probably responding to the decline in HPQ shares after its CEO was ousted and shares got hammered. A sector he sold out was refiners. He sold all his shares in Valero (VLO), Sunoco (SUN), and Tesoro (TSO). Insider Monkey, your source for free insider trading data, not only follows corporate insiders but also keeps an eye on proven hedge fund managers. David Tepper, with an average 30% return for his investors over the last 17 years, has surely proven himself.