Bas Werker

Health Cost Risk: A Potential Solution to the Annuity Puzzle

We find that health cost risk lowers optimal annuity demand at retirement. If medical expenses can be sizeable early in retirement, full annuitisation at retirement is no longer optimal because agents do not have enough time to build a liquid wealth buffer. Furthermore, large deviations from optimal annuitisation levels lead to small utility differences. Our results suggest that health cost risk can explain a large proportion of empirically observed annuity choices. Finally, allowing additional annuitisation after retirement results in welfare gains of at most 2.5% when facing health cost risk, and negligible gains without this risk.

EFFICIENT ESTIMATION OF INTEGRATED VOLATILITY AND RELATED PROCESSES

We derive nonparametric bounds for inference about functionals of high-frequency volatility, in particular, integrated power variance. In the absence of microstructure noise, we find that standard Realized Variance attains the nonparametric efficiency bound, also in case of unequally spaced random observation times. For higher powers, e.g., integrated quarticity, the block-based procedures of Mykland and Zhang (2009) can get arbitrarily close to the nonparametric bounds in case of equally spaced observations. The estimator in Jacod and Rosenbaum (2013) is efficient, also at non-constant volatility, still for equally spaced data. For unequally spaced data, we provide an estimator, similar to that of Kristensen (2010), that can get arbitrarily close to the nonparametric bound. Finally, contrary to public opinion, we demonstrate that parametric information about the functional form of volatility generally leads to a decreased lower bound, unless the volatility process is piecewise constant.

The Composite Iteration Algorithm for Finding Efficient and Financially Fair Risk-Sharing Rules

We consider the problem of finding an efficient and fair ex-ante rule for division of an uncertain monetary outcome among a finite number of von Neumann-Morgenstern agents. Efficiency is understood here, as usual, in the sense of Pareto efficiency subject to the feasibility constraint. Fairness is defined as financial fairness with respect to a predetermined pricing functional. We show that efficient and financially fair allocation rules are in one-to-one correspondence with positive eigenvectors of a nonlinear homogeneous and monotone mapping associated to the risk sharing problem. We establish relevant properties of this mapping. On the basis of this, we obtain a proof of existence and uniqueness of solutions via nonlinear Perron-Frobenius theory, as well as a proof of global convergence of the natural iterative algorithm. We argue that this algorithm is computationally attractive, and discuss its rate of convergence.