The 20% loss the S&P 500 has endured this year made investors search for a bottom. 

But for John Hussman, this is only the beginning.  

Hussman, the president of the Hussman Investment Trust who called the 2000 and 2008 market crashes, said that given where valuation levels started at the market's peak in January 2021 — and where they are now — the damage so far this year has been relatively minor.

"Despite being nearly a year into what we expect to be a far deeper retreat, the relatively shallow loss isn't even surprising," Hussman said in a recent commentary. "The same thing happened in the first year of each of the three deepest post-war stock market collapses: 2000-2002, 2007-2009, and 1973-74."

Hussman's favorite valuation measure — which he believes has the best track record of predicting long-term returns — is market capitalization of non-financial stock-to-gross value added, or total revenue. The current reading of the measure shows stock valuations still near where they were at the peak of the dot-com bubble over two decades ago.

"MarketCap/GVA is our most reliable valuation gauge in market cycles across history, including recent decades. Notice how little impact the 2022 market decline to-date has had on valuations," he said. "Though recent market losses have removed the most extreme speculative froth, our most reliable valuation measures remain near their 1929 and 2000 extremes."

Hussman said his models show the S&P 500 could slump another 60% in the months and years ahead, adding that investors should prepare a "very long, interesting trip to nowhere" for stocks. 

He also said he expects -6% returns over the next 10-12 years for the S&P 500.