martin kremenstein: it started with the boycotts of companies that did business with apartheid southrica, that was really the genesis of this and en it kindf grew up along with the green movement tthrough the 1970s and it kind ofhen grew to incorporate removal ofobacco stos, removal of firearmmanufacturersf nuclear weapon manufacturers. it wasll about excluding companies. >> this exclusion strategy is called divesting, and despite the initial excitement, it led to mixed results. hauke hillebrandt: it is, however, according to modelittle b.lio theory, you have to sacrifice some financial returns. >> destments removed entire sectors like energand tobacco investors' portfolios. when a portfolio is less diversied, its risk goes up. the first of such funds, for example, has historically underperformed the market. but big money is now betting thathis willhange. inis 2020 leer to ceosrically larry nk, the chairman of. blackrock, the world's largest fund manager, came right out and said climate risk is investment risk. main: i don't think there is a choice between plan and profit. when you l