DISCUSSION PAPER PI-0815
Optimal asset allocation strategy for defined-contribution pension plans
with power
utility
Qing-Ping Ma
Optimal asset allocation strategies of defined-contribution pension plans
for members
whose terminal utility is a power function of wealth-to-wage ratio is investigated
in
this paper. The portfolio problem is to maximize the expected terminal utility
in the
presence of three risk sources, interest risk, asset risk and wage risk. A
closed form
solution is found for the asset allocation problem and the optimal portfolio
composition is horizon independent when there is no non-hedgeable wage risk
or
there is no further contribution from wage incomes. When future contributions
from
wage income are hedged by short-selling a wage replicating portfolio, the
optimal
composition of financial wealth on hand (i.e. pension portfolio wealth + short-sold
wage replicating portfolio) is horizon-dependent. The optimal asset allocation
strategy
is equivalent to invest in two mutual funds, one of which is to hedge wage
risk and the
other a speculative fund to satisfy the risk appetite of the plan member.
Keywords : Defined-contribution pension plan; Wage risk; Optimal asset allocation;
Power utility; Hamilton-Jacobi-Bellman equation
