He Invested Through Five Bubbles. He Wrote the Book on Them | What We Learned This Week

Winner-take-all dynamics

Software's natural characteristics create insurmountable first-mover advantages, allowing dominant firms to become price setters rather than price takers.

Regulatory vacuum since 2000

Grantham argues that unlike previous eras where Standard Oil was broken up, government inaction allowed domestic and global monopolies to form unchecked, preventing the competition that historically erodes excess profits.

The growth paradox

While monopolies increase profit margins and inequality, they simultaneously slow GDP growth by suppressing worker compensation and competitive innovation.

Fertile soil requirements

All bubbles begin with 'something new'—such as AI, the end of inflation, or financial deregulation—combined with accommodative monetary conditions that allow speculation to take root.

Escalation triggers

Specific events amplify bubbles into excess, such as the Fed's post-SVB crisis easing that abandoned the inflation mandate despite 62 consecutive months above target, or the 1987 LBO boom driven by Lotus 123 and high-yield debt markets.

Peaking phase recognition

Bubbles progress predictably from root conditions to escalation events to a final peaking phase, with Constant suggesting AI may currently be in the peaking phase following the January 2023 Microsoft OpenAI investment inflection point.

Infrastructure commoditization

AI is transitioning from competitive advantage to standard cost-of-doing-business, which will likely prevent the aggregate profit margin expansion that equity markets currently expect.

Historical parallels

The AI boom mirrors past capital cycles where initial productivity promises preceded massive capital misallocation, suggesting today's capex boom may follow the same pattern as railroads, canals, and previous tech cycles.

Central bank contradiction

Grantham notes that Greenspan cut rates into a 40% market rally after warning of 'irrational exuberance,' illustrating how monetary accommodation often escalates bubble conditions rather than restraining them.