Robert Litterman

At Goldman Sachs Litterman developed the Black–Litterman model together with Fischer Black in 1990.[2][3]

The model solves a seemingly simple yet perplexing problem: it is difficult to consistently estimate expected returns from various assets. The Black–Litterman model solves this problem by making expected returns an output, rather than an input, in the model. The model combines information from market equilibrium with views about returns of assets or combinations of assets, in order to generate the expected returns.

The Black–Litterman model has become one of the standard models widely used by investors around the world to optimize portfolios.[2] Litterman is the author of Modern Investment Management: An Equilibrium Approach, together with Goldman Sachs Asset Management's Quantitative Resources Group.[4]

Shortly after retiring from Goldman Sachs in 2009, Litterman moved, together with several other former Goldman partners such as Mark Tercek and Larry Linden, into the climate and environmental policy world.[5] (Tercek is now the present and CEO of The Nature Conservancy. Linden is the founder of the Linden Trust for the Environment, donating to several climate and environmental causes.)

Litterman serves as director of the World Wildlife Fund,[6] Resources for the Future and Climate Central.[7] He also serves on the economic advisory council of the Environmental Defense Fund,[8] and he serves on the boards of the Julie Wrigley Global Institute of Sustainability at Arizona State University, the Woods Institute for the Environment at Stanford University, the Heller Hurwicz Economics Institute at the University of Minnesota, the Commonfund, and the Climate Leadership Council, founded by Ted Halstead.

Litterman is a staunch advocate for a carbon tax.[1][9] He created the EZ Climate carbon pricing model, joint with Columbia University's Kent Daniel and Gernot Wagner.[10] He leads the Climate-Related Market Risk Subcommittee of the Commodity Futures Trading Commission (CFTC).[11][12]