This paper studies the evolution of China’s exchange rate policy using real options theory. With intervention costs and ongoing uncertainty, intervention involves the exercise of an option. Increased uncertainty increases the value of this option. This “wait and see” effect leads the Central Bank to widen its intervention band. However, increased volatility also produces larger fluctuations in welfare, which creates a “fear of floating.” This induces the Central Bank to set a tighter band. To study this trade-off, our paper incorporates stochastic volatility into a new Keynesian target zone model and then calibrates it to data from China. We find that increased uncertainty leads to a tighter intervention band, both in the data and in the model. Hence, in China, “fear of floating” appears to dominate the “wait and see” effect.

This paper pioneers a Freidlin–Wentzell approach to stochastic impulse control of exchange rates when the central bank desires to maintain a target zone. Pressure to stimulate the economy forces the bank to implement diffusion monetary policy involving Freidlin–Wentzell perturbations indexed by a parameter ε∈ [0,1]. If ε=0, the policy keeps exchange rates in the target zone for all times t≥0. When ε>0, exchange rates continually exit the target zone almost surely, triggering central bank interventions which force currencies back into the zone or abandonment of all targets. Interventions and target zone deviations are costly, motivating the bank to minimize these joint costs for any ε∈ [0,1]. We prove convergence of the value functions as ε→0 achieving a value function approximation for small ε. Via sample path analysis and cost function bounds, intervention followed by target zone abandonment emerges as the optimal policy.