The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.By Carla Pasternak NEW YORK ( Street Authority) -- Banks are among the most hated institutions in the world, as they are seen by many as the epitome of corporate greed. Investors have no love to spare for banks, either. Financials were the worst-performing sector in the S&P 500 in 2011, with losses of more than 20%, compared with about 2% for the overall market. But the sector is diverse, from big money centers such as Bank of America ( BAC) to smaller regional banks such as Huntington Bancshares ( HBAN). There's a big difference between these two groups, and it's not just in their size. While both groups are federally chartered, they operate under different legislation. As a result, most regional banks focus on the traditional banking activities of savings deposits and mortgages and other loans. They devote little, if any, resources to securitizing mortgage loans or hedging with derivatives, as the big banks do. Most regional banks also aren't exposed to risky eurozone debt or faced with the massive mortgage lawsuits of their bigger brethren. With little exposure to subprime mortgages, regional banks largely dodged the debt crisis of 2008. These banks, as represented by the SPDR S&P Regional Banking ETF ( KRE), lost 18% in 2008. By contrast, their big-cap brethren, represented by the SPDR S&P Bank ETF ( KBE) suffered a loss of more than 47%. Regional banks didn't fare as well as their large-cap counterparts in 2009, however, amid concerns that the weak real estate market would affect their residential and commercial real-estate loans. As of March 2010, 54% of the assets of smaller banks were related to real estate, compared with 43% of the 25 largest U.S. banks, according to Bruce Tuckman, author of Fixed Income Securities. But now they are back on the radar screen and starting to attract investor attention. Regional banks gained close to 15% in the past three months, compared with less than 5% for large-cap bank stocks.