BOSTON ( TheStreet) -- The S&P 500 Index, the benchmark for U.S. stocks, is rising for a third consecutive year after a recession decimated corporate profits in 2008 and 2009.But, some stocks are languishing, as their businesses are dogged by weaker demand from customers, higher energy prices or special circumstances. 10 Best-Performing S&P 500 Stocks of 2011 The S&P 500 has fallen from a high of 1,343 on Feb. 18. Uprisings in the Middle East and an earthquake and ensuing nuclear calamity in Japan prompted the sell-off. Still, the stock market has regained a firmer footing in the past week, as investors were pleased by improvement in the U.S. job market. Top-Performing Energy Stocks Picked by Funds The following 10 S&P 500 stocks, the worst of 2011 so far, have fallen fast. Each has been hurt by a turn in sentiment related to business prospects. For opportunistic buyers, these equities may offer value. 10. Carnival ( CCL) owns and operates cruise lines, including Princess and Holland American. Its stock soared 46% in 2010, but is down 16% this year. Adjusted fiscal first-quarter earnings increased 58% to 19 cents, matching the consensus estimate, as sales gained 10%. But, the stock tumbled nearly 5% in reaction to the report as management signaled that revenue would be lower than expected in 2011. Also, higher fuel costs hampered profit growth. A higher gasoline price not only raises Carnival's operating costs, but also deters Americans from taking vacations, as they have less discretionary income.