A peculiar thing happened in 2016. While the Dow Jones industrial average grew by more than 13 percent, college endowments saw nearly a negative 2 percent rate of return. The worst endowment performance took place at the nation’s wealthiest private institutions. Harvard’s endowment alone shrank by $2 billion, a 5-percent decline. Out of the 40 biggest endowments, 35 declined in value.