By Matt Phillips, Alexandra Stevenson and Jack Ewing

New York Times News Service

October is living up to its ominous reputation among stock investors.

Stocks on Wall Street tumbled again Thursday, as choppy early trading gave way to another bout of broad-based selling. The declines were widespread, touching everything from previously high flying tech shares to usually insulated sectors like consumer staples and utilities.

When the dust settled, every sector of the S&P 500 index had dropped, leaving the stock market bench mark down an additional 2.1 percent. That slump followed Wednesday’s 3.3 percent decline, which was the market’s biggest dive in eight months.

So far in October — which looms large in the minds of investors as the month of the 1929 and 1987 crashes — stocks are down 6.4 percent. That puts the month on a pace to be the worst October for stocks since 2008, when they fell nearly 17 percent.

The yield on the 10-year Treasury note ended the day just below 3.15 percent, lower than it had been in several days.

The easing of rates did little to comfort investors who are also worrying about deteriorating relations between Washington, D.C. and Beijing. On Thursday, the Energy Department said it would tighten controls on Chinese imports of civil nuclear technology.

Christine Lagarde, managing director of the International Monetary Fund, warned Thursday that if the tensions between the United States and China continued to escalate, “the global economy would take a significant hit.”