Further Evidence on Technical Trading Profitability and Foreign Exchange Intervention

In this paper we present new evidence on the positive correlation between returns from technical trading rules and periods of central bank intervention. To that end, we evaluate the profitability of a trading strategy based on nearest-neighbour (nonlinear) predictors, which may be viewed as a generalisation of graphical methods widely used in financial markets. We use daily data on the US Dollar/Deutsche mark and US Dollar/Japanese Yen covering the 1 February 1982 - 31 December 1996 period. Our results suggest that the exclusion of days of US intervention implies a substantial reduction in all profitability indicators (net returns, ideal profit measure, Sharpe ratio and directional forecast), being the reduction grater in the US Dollar-Deustchmark case than in the US Dollar-Japanese yen case