Big bank Citigroup ( C) is another name that Renaissance newly initiated in the most recent quarter. Simons and company added 3.7 million shares of Citi to thier portfolio, building a position worth $177 million. Citi is one of the biggest banks in the world, with 1.9 trillion in assets and more than a quarter of a million employees. And it's one of the biggest beneficiaries from the equity rally that's propelled the S&P 500 more than 16% higher this year. >>5 Stocks Poised for Breakouts Like its peers, Citi has made a big about-face in recent years, changing its focus back to conventional banking. As a result, Citi's shareholders are seeing profitability again. Scale matters in the banking business -- that's why Citigroup's $1.87 trillion in assets are worth paying attention to. Despite its size, hefty exposure to emerging markets means that the firm has the ability to tap undersaturated loan markets with burgeoning middle class populations. While those growth opportunities don't come without risks, the relatively vanilla nature of the rest of the financial sector makes it look a whole lot more attractive. But that doesn't mean that Citi's shares are attractive. Granted, they're not toxic, but then again, an abundance of regulatory restrictions and the possibility for more skeletons in Citi's closet makes it look less appealing. If you're looking for exposure to banking stocks, think regional names instead.