Pension Returns Depend on the Start Point

A New York Times article on New York City's pension funds implied that its assumed rate of return going forward is too high based on past returns over a highly selective period:

"But excessive optimism can lead to financial disaster, because regular shortfalls could ultimately leave the city unable to fulfill its required payouts. For years, the investment return expectation was set at 8 percent. In reality, the system’s returns have often fallen well short of that, earning just 2 percent on...