Conditions That Signal Bubble Tops

Jeremy Grantham is one of the greatest investors of all time, and is famous for correctly identifying the four major stock market bubbles of his 60 year investment career. He joins Wilf to discuss the key ideas of his new book The Making of a Perma Bear: The Perils of Long-Term Investing in a Short-Term World and what they mean for investors today.

Jeremy and Wilf explore the factors that drove him to admire value stocks; what makes for good idea generation and decision making when it comes to investing; and the factors he identified that academics missed. 

In particular they explore why quality stocks and momentum remain persistent – and often misunderstood – market inefficiencies, and why this created the opportunity for the extraordinary outperformance he delivered at the firm he founded – GMO (Grantham, Mayo, & van Otterloo). But they also discuss why value is the ultimate gravitational market force that delivers performance over the long term.

Looking at today’s environment, Grantham assesses the Iran War’s impact on oil prices, AI, meme stocks and the “Magnificent Seven”, drawing parallels with 1970s, 1999, 2007 and the post-Covid boom. He sets out the conditions he believes typically lead to a bubble bursting and also tackles longer-term headwinds – from demographics and de-globalisation to climate damage and geopolitical risk – arguing  that these are fundamentally at odds with the near-record valuations investors are currently paying.

Along the way, Grantham discusses his early role in the birth of index investing; his respect for Warren Buffett and Jack Bogle; why most institutions will never tell clients to get out before a crash; and how to know when to “reinvest when terrified”. 

This is a candid, insightful masterclass from one of the defining investment thinkers of the last half-century.

Recorded Monday 13th April 2026. 

You can watch the full video on The Master Investor Podcast YouTube channel

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If you’d like to attend the upcoming Master Investor Show in London on Saturday 25 April, where I’ll be interviewing Jim Mellon amongst others, with over 5000 like minded investors in attendance, then click the link below and use code “MIPOD” for a free ticket: 

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