GMO Research Library and Quarterly Letter
GMO's quarterly letters, white papers and Jeremy Grantham's essays on bubbles, valuation and long-horizon asset allocation. Read them to hear the firm that has argued for mean reversion longer than almost anyone.
Free to read
GMO's research library holds the GMO Quarterly Letter, written in recent years mostly by asset allocation head Ben Inker with colleagues, along with white papers, Viewpoints and Insights pieces from the firm's teams. The best-known items are Jeremy Grantham's essays on bubbles, which argue from historical data that extreme valuations always revert even when timing is impossible.
The library is valuable because GMO's process is explicitly valuation-driven and long-horizon. The letters explain what is priced in, why the firm favors or avoids particular regions and styles, and how it thinks about the career risk of being early. Grantham's pieces also make a broader case on resource limits and climate.
Start with Grantham's bubble essays for the big framework, then read the latest Quarterly Letter for the current argument. The Q3 2026 letter, on how a flood of new equity supply could end an AI-driven bubble, shows the house approach applied to today's market. Pieces are available as web pages and PDFs.
Start with
-
1
Bracing Yourself for a Possible Near-Term Melt-Up (January 2018)
Grantham's checklist for recognizing the final, speculative phase of a bull market.
-
2
Waiting for the Last Dance (January 2021)
His case that US equities had entered a late-stage bubble and what that means for allocators.
-
3
A Catalyst for the AI Bubble Break (Q3 2026 Quarterly Letter)
Ben Inker and John Pease argue that new equity supply, not weak AI demand, may be what ends the boom.