Nerves Rattled in U.S. Equities Amid Ugly Volatility

To Paul Zemsky, the challenge in the stock market is to keep your head while others are losing theirs.

“As an investor, what I’m thinking right now is don’t panic,” said the 52-year-old head of multi-asset strategies at Voya Investment Management LLC in New York. He spoke as the Standard & Poor’s 500 Index staged one the most volatile sessions in three years, rising as much as 1.4 percent and falling 1 percent as West Texas Intermediate crude briefly dipped below $45 a barrel and copper hit its lowest level since 2009.