The Dow ended the day with a loss of more than 640 points, or 1.9%. The S&P 500 and Nasdaq fell 2.1% and 2.6% respectively. All 30 Dow stocks were lower, and only 25 of the stocks in the blue chip S&P 500 index traded higher Monday.Stocks also slumped Friday as the market snapped a four-week winning streak. The markets have rebounded in July and August following a brutal first half of 2022. But the pendulum may be swinging back to pessimism.Concerns are mounting that the Fed is not done with its super-sized rate increases just yet. The Fed lifted rates by three quarters of a percentage point, or 75 basis points, in both June and July. But following the most recent data on consumer and producer prices, which showed that the rate of inflation cooled a bit last month, investors had started to hope that the Fed might raise rates by only a half a point in September.The thought was that inflation was easing and the economy might be slowing. However, the jobs market remains strong and retail sales have held up reasonably well, despite inflation. That’s led more market watchers to predict that the Fed may remain aggressive with rate hikes for the foreseeable future. The odds of another 75 basis point hike versus a half-point increase are now seen as about 50-50. “Market expectations for what the Fed will do has a track record of flipping based on economic data,” said Lindsey Bell, chief money and markets strategist for Ally Invest, in a report Monday. “As long as the Fed is in the driver’s seat, volatility is likely to remain elevated and the market will remain reactionary.”Stocks could be volatile all week as investors wait for Fed chair Jerome Powell to give an eagerly awaited speech at the Kansas City Fed’s annual Jackson Hole symposium on Friday. What’s more, the Fed’s next interest rate decision is not until September 21. So a lot of economic data, including the jobs report and inflation numbers for August, lies ahead. “This has been more like a bull rally in a bear market,” Oktay Kavrak, director of product strategy at Leverage Shares, said about what’s happened with stocks in the past few weeks. “Recession is still a base case and inflation remains stubbornly high. This could be one of those years where the market remains choppy.”Investors are clearly fleeing riskier assets as a result. Meme stocks, such as AMC (AMC), Bed Bath & Beyond (BBBY) and GameStop (GME), were all in the red again Monday following big drops at the end of last week. Bitcoin and other cryptocurrencies also fell Monday and have all plummeted in the past week.