Short Selling and Index Arbitrage Profitability: Evidence from the SGX MSCI and TAIFEX Taiwan Index Futures Markets

There are numerous impediments to market efficiency and index arbitrage in real capital markets, including the uptick rule on short selling, execution risk, market impact costs, regulatory barriers, and capital constraints. Adopting and relaxing the uptick restriction in the Taiwan stock market facilitated a study on whether adjustments in this restriction influence the efficiency and arbitrage of the Singapore Exchange Limited (SGX) and the Taiwan Futures Exchange (TAIFEX) index futures markets. This study examines the above issues using five-minute intraday transaction data and performs an ex post test of arbitrage, ex ante test of arbitrage, and regression analysis. Empirical results indicate that relaxing the uptick rule should improve market efficiency and facilitate long arbitrage, subsequently accelerating the adjustment to no-arbitrage bounds and helping to decrease ex post and ex ante mispricing and underpricing following the relaxation.