We'll start off with the outlier, Citigroup ( C). Last quarter, Pershing Square only added onto four positions in its portfolio -- and Citigroup was the sole firm that Ackman and company have little chance of taking an activist role in. The firm took a bite-sized addition to its Citi stake, adding 4,750 shares in the most recent quarter. That puts Pershing Squares total position worth $267.6 million, or 11.8% of the hedge fund's portfolio. Citi hasn't exactly been the poster child for financial stability lately. The firm, like other big banks, still has a balance sheet that's about as transparent as mud. But Citi has been distancing itself from other banks' dramas lately, a big positive in a year that's been full of government fines and trading losses. At the same time, Citigroup has been quietly raising its financial reserves, boosting its Tier 1 common ratio to meet increased restrictions. Exposure to developing countries is one of the big differences that Citi offers investors. While most of its peers sought to escape the risks of those emerging markets, they fell right into the zero-interest rate traps in Europe and here at home. Because Citi can earn a wider spread on loans in growing countries, it's been able to churn out some enviable performance lately. >>5 Big Stocks Ready to Slingshot Higher By and large, I wouldn't recommend loading up on shares of any big bank in 2012. That said, if you must, you could do worse than Citi right now. Citigroup, which is also one of David Tepper's Appaloosa Management holdings, shows up on a recent list of 4 Large Bank Stock Picks From Deutsche Bank.