Insuring uninsurable income

In an exchange economy where idiosyncratic income is private information, classic optimal contracts achieve efficiency only at the cost of immiserisation: promised utilities drift downward, driving unbounded inequality. This paper proposes an alternative recursive mechanism that shifts risk one period ahead. The mechanism fixes consumption within each period -- postponing all risk by one period -- and, when risk aversion is below a mild bound (condition (8)), this allocation is sequentially efficient. The mechanism keeps promised utilities in a bounded set, avoids immiserisation, and when the initial promise satisfies an explicit inequality linking risk aversion and income variance, it remains budget-balanced in a stationary overlapping-generations society. Thus, efficiency, sustainability, and equality of opportunity can coexist without storage or capital accumulation.