Over half of all companies that make up the broad-based S&P 500 Index, which, as the name implies, is made up of 500 companies, have reported through the end of April. So far profits are expected to rise an astounding 25% versus a year ago, according to Thomson Reuters I/B/E/S. Anything above 10%, a double-digit increase, would be viewed as solid.

Last year, stocks marched higher with only minor pullbacks. When the year ended, the largest peak to trough decline for the S&P 500 Index was just under 3% (St. Louis Federal Reserve data on the S&P 500). It was a year that lacked turbulence and one that rewarded diversified investors. Since the beginning of February, volatility has returned.

February’s early slide saw the S&P 500 Index lose just over 10% in value–an official correction–in just nine trading days. That’s right–nine trading days from an all-time high to a 10% decline which, according to LPL Research, was the quickest on record. Moderate economic growth at home and abroad has been fueling corporate profits.

Any thoughts that 2018 might start with a pause in the bull market were quickly dispelled in the first week of the year. A “buy the rumor, sell the news” view on tax reform has shaken out to be more aptly described as buy the rumor and buy the news. In my opinion, the credit goes to the dramatic reduction in the corporate tax rate—from 35% to 21%, beginning in 2018.