We have put together our database of 13F filings from hundreds of hedge funds and other notable investors following the remaining filings being made public earlier this month. This wave of 13Fs disclose long equity positions as of the end of December 2012. Even with the delay, we’ve developed investing strategies based on 13F activity which can be profitable; for example, the most popular small cap stocks among hedge funds tend to produce an excess return of 18 percentage points per year (learn more about our small cap strategy). We also like to look at which stocks hedge funds like in different sectors. Here are the ten most popular energy stocks: The energy stock that the largest number of filers in our database reported owning was Anadarko Petroleum Corporation (NYSE:APC), a $42 billion market cap oil, gas, and natural gas liquids company.  62 hedge funds reported a position in Anadarko. One of these was billionaire Ken Griffin’s Citadel Investment Group, which increased its holdings by 56% between October and December to a total of 3.5 million shares (see Griffin's stock picks). Anadarko trades at 16 times consensus earnings for next year. Schlumberger Limited. (NYSE:SLB), an oilfield services company, had 55 hedge funds report a position- about even with the number who did for the third quarter of 2012. Fisher Asset Management, managed by billionaire Ken Fisher, had 7.8 million shares of Schlumberger in its portfolio (find Fisher's favorite stocks). While Schlumberger’s revenue was up moderately last quarter compared to the same period in 2011, earnings were down. 54 hedge funds and other notable investors owned supermajor Exxon Mobil Corporation (NYSE:XOM), down from 59 at the end of September. Exxon Mobil- which at one point briefly overtook Apple to become the largest publicly traded U.S. company by market cap- is one of the top picks in the Bill and Melinda Gates Foundation Trust’s portfolio. Research more stocks that the foundation's money is invested in. Acquisition target Nexen Inc. (NYSE:NXY) was owned by 52 filers in our database, with others which we had previously recorded selling as the gap between the transaction price and the market price narrowed during the quarter as the proposed deal overcame Canadian regulatory hurdles. Learn more about merger arbitrage strategies. We tracked 50 hedge funds who owned shares of Schlumberger’s smaller peer, Halliburton Company (NYSE:HAL); Halliburton had actually been slightly more popular in our analysis for the third quarter, but was sold more frequently over the next three months. Billionaire Leon Cooperman’s Omega Advisors closed 2012 with 3.8 million shares in its portfolio (check out more stocks Cooperman liked). See five more energy stocks that were popular among hedge funds: