Despite college students' calls for fossil fuel divestment, an executive at one major investment manager said endowments should avoid investing solely to renewable energy sources. Swapping solar and wind for oil and gas leads to lower returns, said Commonfund's Peter Burns. College students are pressuring their schools to stop investing in fossil fuels, but one of the biggest managers of endowment money says that might not be such a good idea. Commonfund, a Connecticut-based manager which $24.8 billion for nonprofits, continues to see oil and gas as an attractive investment opportunity, executives said at a Tuesday media roundtable.