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Has the sell off of a “Super Bubble” already begun? That’s what investor Jeremy Grantham, cofounder of GMO, believes today. Bloomberg’s Erik Schatzker reports:

Jeremy Grantham, the famed investor who for decades has been calling market bubbles, said the historic collapse in stocks he predicted a year ago is underway and even intervention by the Federal Reserve canโ€™t prevent an eventual plunge of almost 50%.

In aย noteย posted Thursday, Grantham, the co-founder of Boston asset managerย GMO, describes U.S. stocks as being in a โ€œsuper bubble,โ€ only the fourth of the past century. And just as they did in the crash of 1929, the dot-com bust of 2000 and the financial crisis of 2008, heโ€™s certain this bubble will burst, sending indexes back to statistical norms and possibly further.

That, he said, involves the S&P 500 dropping some 45% from Wednesdayโ€™s close — and 48% from its Jan. 4 peak — to a level of 2500. The Nasdaq Composite, already down 8.3% this month, may sustain an even bigger correction.

โ€œI wasnโ€™t quite as certain about this bubble a year ago as I had been about the tech bubble of 2000, or as I had been in Japan, or as I had been in the housing bubble of 2007,โ€ Grantham said in a Bloomberg โ€œFront Rowโ€ interview. โ€œI felt highly likely, but perhaps not nearly certain. Today, I feel it is just about nearly certain.โ€

In Granthamโ€™s analysis, the evidence is abundant. The first sign of trouble he points to came last February, when dozens of the most speculative stocks began falling. One proxy, Cathie Woodโ€™sย Ark Innovation ETF, has since tumbled by 52%. Next, the Russell 2000, an index of mid-cap equities that typically outperforms in a bull market, trailed the S&P 500 in 2021.

Finally, there was what Grantham calls the kind of โ€œcrazy investor behaviorโ€ indicative of a late-stage bubble: meme stocks, a buying frenzy in electric-vehicle names, the rise of nonsensical cryptocurrencies such a dogecoin and multimillion-dollar prices for non-fungible tokens, or NFTs.

โ€œThis checklist for a super bubble running through its phases is now complete and the wild rumpus can begin at any time,โ€ Grantham, 83, writes in his note. โ€œWhen pessimism returns to markets, we face the largest potential markdown of perceived wealth in U.S. history.โ€

Read more here.