Traders work after the closing bell at the New York Stock Exchange (NYSE) on August 12, 2019 at Wall Street in New York City.

Remember the brutal sell-off last year when stocks suffered their worst December since the Great Depression? Something worse than that could happen in days, a Nomura analyst said.

Macro and quant strategist Masanari Takada turned heads earlier this month with his bold call for a "Lehman-like" plunge. He's sticking with this prediction as market sentiment shows no signs of improving, leading him to believe a monster sell-off could arrive this week.

"The U.S. stock market especially is facing its greatest test of the year thus far," Takada said in a note to clients on Monday. Low sentiment is poised to prompt "panic-selling by fundamentals-oriented investors and systematic selling by trend-following technical investors along the way," he said.

Takada's view, the most pessimistic on Wall Street, is based on macro and quantitative data including flows from hedge funds and other players, which showed sentiment is approaching the lowest level of the current cycle. He had predicted the first explosion in the Cboe Volatility Index, aka Wall Street's "fear gauge," which swung to the highest in 2019 on Aug. 5 when China allowed its currency to drop to a level unseen since the financial crisis amid the trade war.

This week is also the last week before the Labor Day weekend. Volumes are typically low at the end of August, which could exaggerate market moves.

The Dow tanked more than 33% in 2008, the year in which Lehman Brothers went bust. The collapse helped catalyze the financial crisis and bring on the Great Recession. By March 2009, the benchmark hit its lowest level of 6,443.27, a peak-to-trough decline of about 55%.