Stock swings that reached twice the five-decade average left the Standard & Poor's 500 Index with the smallest price change in 41 years and utilities, soapmakers and health-care providers at the highest valuations since 2008.

The S&P 500 rose 3.7 percent last week, sending the measure to a gain of 0.6 percent for the year. The last time it moved less on an annual basis was in 1970, when it fell 0.1 percent. Within the gauge, companies least tied to economic growth, such as Biogen Idec Inc. and Hershey Co., increased an average 15.7 percent including dividends, returning 8.2 times more than the index after adjusting for historical price swings. That's the biggest gap since at least 1989.

Bears say that the 2011 performance means there are even fewer stocks worth buying after valuations for defensive shares increased 7.4 percent. With the U.S. showing more signs of growth, bulls say the divergence between those shares and companies most dependent on the economy preceded market-wide rallies in 2001, 2007 and 2009.