Do short selling restrictions destabilize stock markets? Lessons from Taiwan

Short sellers have been routinely blamed for triggering, or exacerbating, stock market declines. The experience of Taiwan provides an interesting case study of the impact of short selling bans on stock returns volatility in a time series framework due to the length of time the short selling ban was in place there. Estimating several variants of an asymmetric GARCH model and a Markov switching GARCH model we find robust evidence that short selling restrictions raise stock returns volatility. The only qualifier is that the impact of short sale bans is a feature of the expansionary phase of business cycles. During recessions this effect dissipates.     

THE EFFECT OF MONETARY POLICY ON CREDIT SPREADS

We analyze the effect of monetary policy on yield spreads between corporate bonds with different credit ratings over the business cycle. We use futures contracts to distinguish between expected and unexpected changes in the Fed funds target rate and several indicators to distinguish between different phases of the business cycle. In line with the predictions of imperfect capital market theories, we find that yields on corporate bonds with low credit ratings widen (narrow) with respect to those with high credit ratings following an unexpected increase (decrease) in the Fed funds target rate during recession periods. Several tests suggest that our results are robust to outliers, potential endogeneity problems, empirical specification, control variables, countercyclical risk premium in futures, and alternative definitions of credit spreads and economic conditions.