Stocks tumbled yet again on Thursday, a day after the Federal Reserve pushed forward with another interest-rate increase and offered few signs that it would sharply slow the pace of monetary tightening as many had hoped.

The S&P 500-stock index declined 1.6 percent, and the Dow Jones industrial index fell 2 percent. The tech-heavy Nasdaq composite fell 1.6 percent, pushing it 19.5 percent below its late-August peak. A decline of 20 percent marks the start of a bear market.

On its own, the broader S&P 500 is down more than 15 percent from its peak, close to entering a bear market and ending the long bull rally that began in early 2009.

“There’s just a constant selling pressure,” said Paul Hickey, a founder of the Bespoke Investment Group, a financial market research firm in Harrison, N.Y. “It’s just any excuse is an excuse to sell.”