A trader works at the New York Stock Exchange in New York, the United States, on Aug. 5, 2019. U.S. stocks plunged on Monday as investors worry that U.S. President Donald Trump’s threatened new tariffs on Chinese imports will worsen trade prospects. The Dow Jones Industrial Average decreased 767.27 points, or 2.90 percent, to 25,717.74. The S&P 500 fell 87.31 points, or 2.98 percent, to 2,844.74. The Nasdaq Composite Index was down 278.03 points, or 3.47 percent, to 7,726.04. (Photo by Guo Peiran/Xinhua via Getty Images)Guo Peiran | Xinhua News Agency | Getty ImagesThe market rebound this week hasn’t convinced the strategist who predicted a “Lehman-like” sell-off for late August or early September that the risk is completely off the table.Nomura macro and quant strategist Masanari Takada made waves earlier this month with his prediction of a crisis-level plunge to arrive as soon as late August. With a key speech from the Federal Reserve’s chairman on deck and the bond market’s repeated recession warnings, the likelihood of a sell-off that catastrophic is still not zero, according to the strategist. “Although the likely magnitude of any second bottoming looks to have declined, the risk of a vol-up scenario playing out at the end of August or early September has not been completely eliminated, in our view,” Takada said in a note to clients Thursday.The market took a huge beating last week with the Dow Jones Industrial Average suffering its worst day of the year on Aug. 14 when the yield curve briefly inverted, fueling worries of a recession. Stocks have rebounded since but the Dow is still down more than 2% in August. The imminent risk for the market meltdown is Fed Chair Jerome Powell’s speech on Friday at the central bank’s annual Jackson Hole, Wyoming, symposium, the strategist said. “The current equity rally seems largely driven by wishful thinking,” Takada said. “Investors should be on their guard until it becomes clear just how dovish Fed Chair Jerome Powell will lean in his comments at Jackson Hole.”Stocks turned lower Thursday in a sharp move after a third trigger of the recession indicator and weak U.S. manufacturing data. The major averages then recovered as traders decided to wait for Powell’s remarks.If the speech from the Fed chair turns out to be a disappointment, global macro hedge funds would start fleeing the market again, stopping the S&P 500 from breaking above 2,960, the strategist said. The benchmark closed Thursday’s trading at 2,924.43.Deeper inversion?Since Takada’s Lehman call, the bond market has flashed a recession signal three times as the spread between the yield on the 10-year Treasury note and that of the 2-year note turned negative briefly on Aug. 14 and Wednesday and Thursday. A deeper inversion could prompt those buy-and-hold investors to dial back their exposure to bonds from stocks, deepening the equity sell-off, the strategist said. “It still seems possible that longer-term investors could shift to more conservative investment stances if the 2yr-10yr curve inverts again, and more deeply,” Takada said. “Longer-term players could gradually shift their investment weightings from stocks toward bonds if concerns over a global economic slowdown persist.”The yield curve inverted for a third time in less than two weeks on Thursday as investors became worried that the Fed won’t save the economy from recession. Two Fed officials told CNBC that they don’t see the case for additional interest rate cuts following the central’s bank quarter-point reduction in July.