Earnings reports by U.S. companies only seem to matter any more when they are disappointing. The reaction to first-quarter results from components of the S&P 500 Index shows as much. Shares of companies whose first-quarter profit beat analysts’ consensus estimate gained less than 0.1% on average in the first day of post-earnings trading, according to data compiled by Bloomberg. It was the third quarter in a row in which the initial response to better-than-expected results was lackluster. First-quarter earnings that were lower than estimates, by contrast, were followed by an average decline of more than 2%.