Never before has a rally in the U.S. stock market gone on this long without a Federal Reserve interest-rate increase. While Standard & Poor’s 500 Index price-earnings ratios are far from records, they’ve shown no ability to expand after the U.S. central bank starts raising rates, according to data compiled by Goldman Sachs Group Inc. and Bloomberg. It’s something else to worry about as the Fed prepares to lift rates in an economy that is still far from booming.