Many educational endowments and other investment organizations are struggling with the question whether to comply with the widespread demands of students and other constituencies to divest their fossil fuel stocks. Some have announced decisions to divest, whereas others have announced decisions not to divest. Although Yale University announced that it would not divest, David Swensen, its chief investment officer, wrote a letter to Yale’s external investment managers emphasizing that in analyzing potential investments, they should favor companies that consider the effects of climate change.