Health care stocksare up the most in 2011, with a gain of 12.7 percent, followed by energy and consumer staples, rising 11.2 and 8.1 percent, respectively.
Financials are the only companies down year-to-date, with a loss of 2.5 percent. (Read Goldman Sachs' revised 2011 S&P 500 target.)This year's gains in health care are, in part, a rebound from a 0.7 increase in 2010, when health care finished the year as the worst-performing sector, behind technology and utility stocks.
In 2010, consumer discretionary, industrials and materials were the best-performing sectors, up over 19 percent for the year.
So far in 2011, health care companies in the S&P 500 have an average gain of 15.8 percent. Managed health care and distributors are up the most, 35.5 and 19.7 percent, respectively.
And of the 52 stocks that constitute the sector, only five are trading in negative territory for the year: Hospira, Varian Medical, Tenet Healthcare , Life Technologies and Boston Scientific.
Here is a look at the best-performing stocks in the top sectors year-to-date, along with their performance so far in May. (Also, check out our slideshow of 20 Stocks With Potential to Pop.)