Another day of big losses knocked U.S. stocks to their lowest levels in more than a year Monday. Investors dumped high-growth technology and retail companies as well as steadier, high-dividend companies. Oil fell below $50 a barrel for the first time since October 2017.

On Monday:

The S&P 500 index sank 54.01 points, or 2.1 percent, at 2,545.94.

The Dow Jones Industrial Average retreated 507.53 points, or 2.1 percent, to 23,592.98.

The Nasdaq composite tumbled 156.93 points, or 2.3 percent, to 6,753.73.

The Russell 2000 index shed 32.67 points, or 2.3 percent, to 1,378.14.

For the year:

The S&P 500 is down 127.67 points, or 4.8 percent.

The Dow is down 1,126.24 points, or 4.6 percent.

The Nasdaq is up 149.66 points, or 2.2 percent.

The Russell 2000 is down 157.37 points, or 10.2 percent.