Jeremy Grantham

Grantham was born on 6 October 1938 in Ware, Hertfordshire, and grew up in Doncaster. He studied economics at the University of Sheffield. In 1966, he completed an MBA at Harvard Business School.

Grantham's investment philosophy can be summarised by his commonly used phrase "reversion to the mean". Essentially, he believes that all asset classes and markets will revert to mean historical levels from highs and lows. His firm seeks to understand historical changes in markets and predict results for seven years into the future. When there is deviation from historical means (averages), the firm may take an investment position based on anticipated return to the mean. The firm allocates assets based on internal predictions of market direction.

Grantham has been described as a contrarian investor and permabear. He named his 2026 book about booms and busts of the past half century The Making of a Permabear: The Perils of Long-term Investing in a Short-term World. It was co-written with Edward Chancellor.

In 1971, Grantham helped established one of the earliest index funds at Batterymarch Financial Management. The idea was unusual at the time and the fund was not a success.

Grantham and his wife, Hannelore, established the Grantham Foundation For the Protection of the Environment in 1997. Substantial commitments have been made to Imperial College London, the London School of Economics, and the University of Sheffield to establish the Grantham Institute – Climate Change and Environment, the Grantham Research Institute on Climate Change and the Environment, and the Grantham Centre for Sustainable Futures, respectively, which will enable the institutions to build on their extensive expertise in climate change research. The Grantham Foundation for the Protection of the Environment's 2011 tax filing shows the Foundation donated $1 million to both the Sierra Club and to The Nature Conservancy and $2 million to the Environmental Defense Fund that year. The Foundation has also supported Greenpeace, the World Wide Fund for Nature, Rare, and the Smithsonian. From 2006 to 2012, The Grantham Foundation for Protection of the Environment funded a $75,000 prize for environmental journalism. It was administered by the University of Rhode Island's Metcalf Institute for Marine & Environmental Reporting.

In August 2019, Grantham dedicated 98% (approximately $1 billion) of his personal wealth to fight climate change. He believes that green technologies are profitable investments in the long run, claiming that decarbonizing the economy will be an investing bonanza for those who know it's coming.