A small hedge fund called Engine No. 1 shocked the oil industry recently when it triumphed in an aggressive fight against ExxonMobil to win three seats on the company’s board. Engine No. 1 is one of a growing crop of hedge funds that engage in impact investing, whereby investors buy a stake in a company with the hopes of retooling that company’s strategy or values—in this case, Exxon’s flagging response to climate change, which has contributed to the company’s stock value steadily declining over the last five years. This case asks students to discuss Engine No. 1’s strategy of impact investing and what changes the fund’s newly won board seats might introduce to both Exxon and the oil industry in general.