Labor economist, Teresa Ghilarducci, has proposed having state pension funds run retirement plans for companies. New York City's comptroller, John Liu, is interested because his city is in "the early stages of a burgeoning retirement crisis," where over a third of all retirement-age households had nothing to rely on except Social Security. Ghilarducci's proposal is a cash-balance pension, a hybrid that combines features of a 401(k) plan with those of a traditional pension plan. Workers can see their benefits as an account balance, but the assets that secure the benefits are held in a pooled trust. Ghilarducci developed her proposal in part by studying countries like Sweden where modified cash-balance pensions helped keep governments from promising more retirement income than their national economies could deliver. Opponents criticize big pension systems because they underestimated the cost of providing conventional pensions and failing to anticipate market crashes.