Another broad stock market sell-off today deepened Wall Street’s losses from last week, leaving the S&P 500 with its biggest slide since mid-June.

The benchmark index fell 2.1%, nearly doubling its losses from last week, when it broke a four-week winning streak. The Dow Jones Industrial Average slumped 1.9% and the Nasdaq dropped 2.5%.

Technology companies and retailers had some of the heaviest losses. Smaller company stocks also lost ground, pulling the Russell 2000 index 2.1% lower.

The latest market slide comes as investors grapple with uncertainty over when the highest inflation in decades will ease significantly, how much will the Federal Reserve have to raise interest rates in order to get it under control and how much will the rate hikes slow the economy.

Wall Street will be looking for insight into these unknowns later this week, when the Federal Reserve holds its annual meeting in Jackson Hole, Wyoming.

“Volatility spiked as investors are increasingly nervous about what they might hear from officials at the Fed’s upcoming Jackson Hole symposium,” said Jeffrey Roach, chief economist for LPL Financial.

The S&P 500 fell 90.49 points to 4,137.99. The Dow lost 643.13 points to close at 33,063.61, while the Nasdaq fell 323.64 points to 12,381.57. The Russell 2000 gave up 41.60 points to 1,915.74.

Some 95% of the stocks in the S&P 500 fell. Technology companies, retailers, banks and communications services stocks accounted for a big share of the index’s slide. Microsoft fell 2.9% and Target fell 3%. JPMorgan dropped 1.7% and Netflix slid 6.1%.

Movie theater operators also fell in choppy trading following news that Cineworld is considering filing for Chapter 11 bankruptcy protection. The industry is still struggling to recover from the virus pandemic. AMC Entertainment fell 5.5% and Cinemark fell 5.8%.

Bright spots in the market included Signify Health, which jumped 32.1% after The Wall Street Journal reported that Amazon would bid for the company.

Bond yields gained ground. The yield on the 10-year Treasury, which influences rates on home mortgages and other loans, rose to 3.03% from 2.97% late Friday.

The broader market’s losses come on the heels of a weekslong rally. Investors are trying to figure out where the economy goes from here as stubbornly hot inflation hurts businesses and consumers. Record-high inflation also has investors focusing on central banks and their efforts to fight high prices without further damaging economic growth.

“You’ve had quite a rally and there’s reason to not be sure where we’re going from here,” said Tom Martin, senior portfolio manager with Globalt Investments. “There’s still decent potential for a recession.”

Minutes last week from the Federal Reserve’s July board meeting affirmed plans for more rate hikes despite signs of weaker economic activity. Traders worry aggressive steps to slow the economy might go too far and bring on a recession. The U.S. economy has already contracted through the first half of 2022 and Wall Street will get more information on Thursday when the government releases an updated report on the U.S. economy for the second quarter.

Investors are also looking ahead to this week’s Federal Reserve conference for signals about more possible U.S. rate hikes to cool surging inflation. Fed Chair Jerome Powell is scheduled to give a speech on Friday morning at the central bank’s annual meeting in Jackson Hole, which starts Thursday.

The Fed is holding its meeting following a heavy week of company and economic data that showed inflation is still squeezing the economy, but consumer spending remains resilient. Falling gasoline and food commodity prices, for wheat and corn, have helped relieve some of that pressure. That helped essentially stall inflation’s advance in July, though prices still remain stubbornly high.

“I don’t think we’re out of the woods yet on inflation,” Martin said. “We still don’t really know how inflation is going to pan out and what the Fed is going to do.”