# Jeremy Grantham says this is 'the most expensive market in 'American history'

> **Open Intelligence Dossier** · First detected: 2026-06-26 17:07 UTC · Category: Business

## Executive Summary
Jeremy Grantham characterizes the current U.S. stock market as the most expensive in American history, citing the ongoing AI boom as a primary factor.

## Intelligence Brief
Jeremy Grantham has issued warnings regarding the valuation of U.S. equities, describing the current market as the most expensive in American history. He indicates that the surge in artificial intelligence interest has pushed stock prices to record levels. Grantham further warns that competition within the AI sector may result in vicious cycles that could negatively impact technology profits.


Coverage from CNBC, Quartz, and Seeking Alpha highlights Grantham’s calls for investors to exit U.S. equities in anticipation of a potential market decline. Reports from eciks.org and A Wealth of Common Sense discuss the broader context of spotting market bubbles and assessing the sustainability of current AI-driven valuations. Future developments remain dependent on market performance and the realization of competitive pressures within the AI sector.


Coverage does not yet specify a timeline for potential shifts in equity valuations or the response of major market indices to these warnings.

## Multi-Source Evidence Table
| Source Outlet | Headline | Verification URL |
|---|---|---|
| Seoul Economic Daily | Billionaire Who Foresaw Dot-Com Bubble Warns AI Bubble Will Burst Within Years | [Source Link](https://news.google.com/rss/articles/CBMiowFBVV95cUxNOEVTNzhoTGJjUEVrYVNlVzByRFFtdjUwMVpkMVdVV1dtWmR6blhoZ09Nak52UkxNT09MTUxncTNuMHlXbkp0NUVZd1J5bFZiMFVqd1gxZGtUdjBQOTU5RzU4WWdiWTVzcVFWQjREcS1uREZtOXYzWWEzemhrT3FfZlFfeUxFb2RRb0lhOUxSc2F2QW4wUVlmbS1LRWFuNENkZU9r?oc=5) |
| thestreet.com | Wall Street veteran warns of epic stock market crash | [Source Link](https://news.google.com/rss/articles/CBMimwFBVV95cUxQTjJ3TDZmVE44aTc1LXloWEpDRVpib0RwQV9yQUtKR2JTblE1UFVFSDU2Q2lLV0RYVkpBb01xRGtNdjIzY2Q1dWZ5RUd5eVFWaUdNV0U4V3VTaUdHSXJKaUlGYUVPUFlER2dWZUdxRVdYMVlfVmhpUWk1Szl3VUZZYzFsUmQ3YnFKaXBRYzkxNFdrSFlPLXVVLTREWQ?oc=5) |
| TradingView | Legendary Investor Jeremy Grantham Warns U.S. Stocks Could Crash 70% | [Source Link](https://news.google.com/rss/articles/CBMixAFBVV95cUxPcWJyT1lUQXVpQVhFamo2aWlHQXFiVndWVEUzWUpYNTB0T3hva1R0NXV6TnhIMURWalpRaVRYdkd5M1FEdmp4OVlxWHNHZHYtaFBEa3NNX0pYV2ZYdlhvQVl1d0taQ1U5WnR4YmEzX1FjeE1BeE1hMDdwUHpVR2Q4ZEhheS1fLVM1S2V3N0xsYzdxLThHb3lpalVQcHR6eUI4RDRoNjVnbjctOGg2bkVPTnRoQVV0YVVYNFFCVmJPS3YyZGpY?oc=5) |
| 24/7 Wall St. | Jeremy Grantham Warns U.S. Stocks Could Plunge 70% in the Most Expensive Market in History | [Source Link](https://news.google.com/rss/articles/CBMizAFBVV95cUxNa0lqMC1NZW5UV1pXZnpVcmlaTHhZaUFfNmp2RnFRV2hfTHRadmo4Z19XZ1lES05UVHdCeUoyRTJweU1IOTExeDY0U29NdnhVcEl2TW1uaUF1akI3SUxiakFtZTVLWjBfMWplVzJEN2VVbk44VE1odkFNV2c1VUlVa3E1aDU1S0w3dGNzWTYwYWIyZzJ0Q2ExSlhSa29YT19HM3FHRmR1TW0zOFJwR0diTmpDUVphQWU1WkRiUUcwYkdJd0VWOWNNeFZwV1g?oc=5) |
| Yahoo Finance | Jeremy Grantham: How to invest like a stock market legend | [Source Link](https://news.google.com/rss/articles/CBMiogFBVV95cUxPeHBMVk5SVDAxRlRKMVpxUE1tYzFfcUFac19Vd0JXLXM2REhJa3dDVkIwbnRJSk9RYjRnV0NtNm42RVoxWlBVbUZyVE14YlBiY013bTNwRmxwVjBJOG1BekZPbERaZEoyaEtFNXJVdTFaNTZEQVZpRC1nR1E0SVZlZmRPQ0VGckdCX0RPTnpoRUdiSE91bGRGeGFSWGhyb1pVMmc?oc=5) |
| eciks.org | Grantham warns AI competition will be ‘vicious,’ draining tech profits | [Source Link](https://news.google.com/rss/articles/CBMif0FVX3lxTE5teWg3TUgzaVV1cmJfbVJyYzkzM0F5Ri1HLXlCU080Y2RPYTkyeDJOMmJzRTBmX0lRWXNYTzgwNXp3UFMwMFU5ZnJlZDNCdWEwX3Z3NWdXME51OFpvOHQ3Z0JtMkZnTDBiV2VBWmcyV2o2ZGVJdHpvOFg3QUF3SGs?oc=5) |
| A Wealth of Common Sense | Spotting Bubbles and Calling Tops | [Source Link](https://news.google.com/rss/articles/CBMigAFBVV95cUxNekNWUmdlMW9RdGJlSTBETTljTE1TcGxObzBCdGhyejVEMlYzTUFzVVpESmlfSFMwaUwtR0REcFR0N3d2WE16bll3dFF0dkRkRW15Rm8tTW9rUlZwWnAzYUhIcVQ2LUVuSlJsOWFxUGNqZ3lpRGdiSlhqaWJ3a1BYaw?oc=5) |
| qz.com | Jeremy Grantham warns AI boom pushed U.S. stocks to record high | [Source Link](https://news.google.com/rss/articles/CBMid0FVX3lxTE9PRzdMcFcwdThWVTFMNFllYkVMekdoTllJazlrTEJIdmVKYkVVU3BlbzJETi1pcFlRLU4xWVhhWW5vR2JHVnZwdXdrQXNKS2J4TVNzbzEzd2ZpaV9BRVY3cHhQbnNTbjFaUFUtZzlnYThuOVZSRnBN?oc=5) |
| Seeking Alpha | Sounding the AI alarm, Grantham says to flee U.S. equities before epic crash (SPY:NYSEARCA) | [Source Link](https://news.google.com/rss/articles/CBMisAFBVV95cUxNdldoMkp4ekN6T1V2WHhtX2pjdUQzc3JHTjZ0NWtPQXd6b0tGcFFhMC05cUZmTDBfcHpXZlpXVDJEOEU5SWFCSG44OEdGRnBEeXR2Q0NVNGFZNEtrVkNWeFozcWMydU1KejlkMVVYUVhiQ0o2MkVGR0VzYWpOX19iWXJkdHNiOTFLSzNUOHJTYXVoZ3VBZGtqam1nMjJtd2E3cUNYVnVzeWJVX2dIbXBVQw?oc=5) |
| CNBC | Jeremy Grantham says this is 'the most expensive market in 'American history' | [Source Link](https://news.google.com/rss/articles/CBMisAFBVV95cUxOajR3eDA3OVB0aHV4aWx4ak1lM2RlTUNJek16dmx4RWo5NFIzY1JsdWRvM1FDckxxYU1FNmVlWWl6MWM4WVUwYjg3dDZpX2I2emtVaHJNTm44RE8xaGZPcmZSODRpY0dHdWV4czlDbjhXNDNYUzFBQzFsMDBpSWdkR0ZCaXdwd1gtZlFOOG9XSmxESzlfMmtGc3BjVHNocUV4WGI4UjR4NmE5OUxZZldHM9IBtgFBVV95cUxQbV9MYlRYcFRzS0hlQS1nOGZmMEo3RDlfWG1JeTJtaTU2VExHdXR4VGlQQlNkU0VnNFVBVUtvQ0lPY1JVOEJoLVRoZDkxbUctUXJCalI3eVB4NldvSzJ0TEtOdEM5Qkl0bkVoQy1CSmdmblkwNWdITGVpUHlnVW1pMmhWWndHQXM2UjhHYldZWU5iSkF5bTlCU2tkVHBtcjRRQy1) |

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*Canonical Source: https://pulse.byoviral.com/trend/2026-06-26/jeremy-grantham-says-this-is-the-most-expensive-market-in-american-history*