Lessons from the evolution of foreign exchange trading strategies

The adaptive markets hypothesis posits that trading strategies evolve as traders adapt their behavior to changing circumstances. This paper studies the evolution of trading strategies for a hypothetical trader who chooses portfolios from foreign exchange (forex) technical rules in major and emerging markets, the carry trade, and US equities. The results show that a backtesting procedure to choose optimal portfolios improves upon the performance of nonadaptive rules. We also find that forex trading alone dramatically outperforms the S&P 500, with much larger Sharpe ratios over the whole sample, but there is little gain to coordinating forex and equity strategies, which explains why practitioners consider these tools separately. Forex trading returns dip significantly in the 1990s but recover by the end of the decade and have been markedly superior to an equity position since 1998. Overall, trading rule returns still exist in forex markets—with substantial stability in the types of rules—though they have migrated to emerging markets to a considerable degree.     

Country-specific equity market characteristics and foreign equity portfolio allocation

Do country-specific equity market characteristics explain variations in foreign equity portfolio allocation? We study this question using comprehensive foreign equity portfolio holdings data and different measures of country-specific equity market factors for 36 host countries. Employing panel data econometric estimations, our investigation shows that foreign investors prefer to invest more in larger and highly visible developed markets which are more liquid, exhibit a higher degree of market efficiency and have lower trading costs. The findings imply that by improving the preconditions necessary for well-functioning capital markets, policymakers should be able to attract higher levels of foreign equity portfolio investments.     

Currency momentum strategies

We provide a broad empirical investigation of momentum strategies in the foreign exchange market. We find a significant cross-sectional spread in excess returns of up to 10% per annum (p.a.) between past winner and loser currencies. This spread in excess returns is not explained by traditional risk factors, it is partially explained by transaction costs and shows behavior consistent with investor under- and overreaction. Moreover, cross-sectional currency momentum has very different properties from the widely studied carry trade and is not highly correlated with returns of benchmark technical trading rules. However, there seem to be very effective limits to arbitrage that prevent momentum returns from being easily exploitable in currency markets.     

Foreign exchange risk pricing and equity market segmentation in Africa

This work is the first to investigate simultaneously the occurrence of unconditional currency risk pricing and equity market segmentation in Africa’s major stock markets. The multi-factor asset pricing theory provides the theoretical framework for our model. We find strong evidence suggesting that Africa’s equity markets are partially segmented. However, we find insufficient evidence to reject the hypothesis that foreign exchange risk is not unconditionally priced in Africa’s stock markets. This result is robust to alternative foreign exchange rate-adjusted return measures. These findings suggest that international investors can diversify into Africa’s equity markets without worrying about unconditional risks associated with foreign exchange rate fluctuations.     

A momentum trading strategy based on the low frequency component of the exchange rate

In this paper, we develop a momentum trading strategy based on the low frequency trend component of the spot exchange rate. Using kernel regression and the high-pass filter of Hodrick and Prescott [Hodrick, R., Prescott, E., 1997. Post-war US business cycles: An empirical investigation. Journal of Money, Credit and Banking 29, 1–16], we recover the non-linear trend in the monthly exchange rate and use short-term momentum in this to generate buy and sell signals. The low frequency momentum trading strategy offers greater directional accuracy, higher returns and Sharpe ratios, lower maximum drawdown and less frequent trading than traditional moving average rules. Moreover, unlike traditional moving average rules, the performance of the low frequency momentum trading strategy is relatively robust across different time periods. The low frequency momentum trading strategy is also robust to the choice of smoothing parameter (in the case of the HP filter) and the distribution and bandwidth parameter (in the case of kernel regression) over a wide range of values.     

Momentum and mean reversion across national equity markets

Numerous studies have separately identified mean reversion and momentum. This paper considers these effects jointly. Our empirical model assumes that only global equity price index shocks can have permanent components. This is motivated in a production-based asset pricing context, given that production levels converge across developed countries. Combination momentum-contrarian strategies, used to select from among 18 developed equity markets at a monthly frequency, outperform both pure momentum and pure contrarian strategies. The results continue to hold after corrections for factor sensitivities and transaction costs. They reveal the importance of controlling for mean reversion in exploiting momentum and vice versa.     

Forecasting Emerging Market Exchange Rates from Foreign Equity Options

The use of derivatives to infer future exchange rates has long been a subject of interest in the international finance literature. With the recent currency crises in Mexico, Southeast Asia, and Brazil, work on exchange rate expectations in emerging markets is of particular interest. For some emerging markets, foreign equity options are the only liquid exchange‐traded derivatives with currency information embedded in their prices. Given that emerging markets sometimes undergo currency realignment with discrete jumps in their exchange rate, estimation of risk‐neutral probability density functions from foreign equity option data provides valuable evidence concerning market expectations. To illustrate the use of foreign equity options in estimating market beliefs, we consider Telmex options around the 1994 peso devaluation and find evidence that markets anticipated the change in the Mexican government's foreign exchange policy.     

The role of shorting,firm size,and time on market anomalies

We examine the role of shorting, firm size, and time on the profitability of size, value, and momentum strategies. We find that long positions make up almost all of size, 60% of value, and half of momentum profits. Shorting becomes less important for momentum and more important for value as firm size decreases. The value premium decreases with firm size and is weak among the largest stocks. Momentum profits, however, exhibit no reliable relation with size. These effects are robust over 86 years of US equity data and almost 40 years of data across four international equity markets and five asset classes. Variation over time and across markets of these effects is consistent with random chance. We find little evidence that size, value, and momentum returns are significantly affected by changes in trading costs or institutional and hedge fund ownership over time.     

Order flow, bid-ask spread and trading density in foreign exchange markets

This paper examines the implications of market microstructure for foreign exchange markets. We argue that the usual order flow model needs to be recast in broader terms to incorporate the transaction costs of liquidity and the limitation of price discovery through order flows that involve low trading density currencies. Using a daily data set, we find that order flows are inadequate when it comes to explaining the changes in the low trading density currencies. Alternatively, within the high trading density, both order flows and bid-ask spreads significantly affect the foreign exchange rate returns. Our findings suggest that the order flow model is better at incorporating these microstructure effects except for some currencies with a very high level of trading density.     

Herding and the role of foreign institutions in emerging equity markets

This study examines herding surrounding qualified foreign institutional investors (QFIIs) in an emerging equity market. Using five years of weekly order flow data, I find that, when QFIIs increase (decrease) their weightings in particular sectors, dealers', margin traders', and mutual funds' holdings/weightings likewise increase (decrease) during the same and following weeks, despite controls for return and trading momentum. This herding is potentially destabilizing as prices overshoot and mean revert highlighting the potential negative impact of this level of transparency and of the policy of disclosing QFII trading in emerging markets.     

Uncovered Equity Parity and rebalancing in international portfolios

Portfolio rebalancing is a key driver of the Uncovered Equity Parity (UEP) condition. According to UEP, when foreign equity holdings outperform domestic holdings, domestic investors are exposed to higher exchange rate exposure and hence repatriate some of the foreign equity to decrease their exchange rate risk. By doing so, foreign currency is sold, leading to foreign currency depreciation. We examine the relationship between U.S. investors' portfolio reallocations and returns and find some evidence consistent with UEP: Portfolio shifts are related to past returns in the underlying equity markets. But we argue that a motive other than reducing currency risk exposure is likely behind this rebalancing. In particular, U.S. investors rebalance away from equity markets that recently performed well and move into equity markets just prior to relatively strong performance, suggesting tactical reallocations to increase returns rather than reduce risk.     

Intraday trading volume and international spillover effects

The objective of this paper is to explore whether lagged trading activity in one market contributes to the return and volatility process in other markets, using 5-min concurrent data from German and British equity market. Our results lend support to our initial premise that if international investors have access to the same information set as domestic traders, then after observing foreign trading activity, market makers adjust prices to reflect their expectation of the security value, conditional upon all available information, including prior trades. Our findings clearly indicate that intraday trading volume contains predictive power for cross-border return and volatility processes. Moreover, these volume effects are found to be asymmetric in the sense that the impact of positive volume changes upon foreign stock market volatility is greater than is the impact of negative changes.     

Momentum trading,mean reversal and overreaction in Chinese stock market

The vast majority of the literature reports momentum profitability to be overwhelming in the US market and widespread in other countries. However, this paper finds that the pure momentum strategy in general does not yield excess profitability in the Chinese stock markets. We find instead strong mean reversion with an average half-life slightly shorter than 1 year. A pure contrarian investment strategy produces positive excess returns and in general outperforms the pure momentum strategy. Furthermore, momentum may interact with mean reversion. A strategy based on the rolling-regression parameter estimates of the model combining mean reversion and momentum generates both statistically and economically significant excess returns. The combined strategy outperforms both pure momentum and pure contrarian strategies. We conduct a number of robustness tests and confirm the basic findings. Collectively, our results support the overreaction hypothesis.     

Trading behavior and investment performance of U.S. investors in global equity markets

This study is prompted by the growing importance of global equity investments as international investment opportunities expand. Specifically, the focus is to investigate: (1) momentum strategies in international equity markets, (2) investment performance in these markets from the perspective of U.S. investors, and (3) effects of making risk adjustments and momentum trading adjustments when evaluating investment performance. Eighteen emerging markets and eighteen developed markets are included in the study over the period 1992–2003. The basic conclusions are that markets reflect winners-momentum trading and losers-contrarian trading. Momentum effects on investment performance are strong but risk-taking effects are weak.     

Tactical allocation in commodity futures markets: Combining momentum and term structure signals

This paper examines the combined role of momentum and term structure signals for the design of profitable trading strategies in commodity futures markets. With significant annualized alphas of 10.14% and 12.66%, respectively, the momentum and term structure strategies appear profitable when implemented individually. With an abnormal return of 21.02%, our double-sort strategy that exploits both momentum and term structure signals clearly outperforms the single-sort strategies. This double-sort strategy can additionally be utilized as a portfolio diversification tool. The abnormal performance of the combined portfolios cannot be explained by a lack of liquidity, data mining or transaction costs.     

Investor type trading behavior and trade performance: Evidence from the Thai stock market

This paper examines the trading behavior and decomposes the trading performance of foreign, individual and institutional investors as well as proprietary traders in a dynamic emerging stock market, the Stock Exchange of Thailand. Foreign investors follow a positive feedback, momentum strategy and are good short term market timers but have poor security selection performance in poor markets, thus suggesting that they have a macro (market timing) but not a micro (security selection) informational advantage relative to local investors. Institutions and proprietary traders have poor security selection trading performance. Individuals display herding behavior and have fairly good security selection performance, but individual investors appear to compensate proprietary traders for the provision of short term liquidity by proprietary traders, so individuals' security selection gains are canceled out by market timing losses.     

Time series momentum

We document significant “time series momentum” in equity index, currency, commodity, and bond futures for each of the 58 liquid instruments we consider. We find persistence in returns for one to 12 months that partially reverses over longer horizons, consistent with sentiment theories of initial under-reaction and delayed over-reaction. A diversified portfolio of time series momentum strategies across all asset classes delivers substantial abnormal returns with little exposure to standard asset pricing factors and performs best during extreme markets. Examining the trading activities of speculators and hedgers, we find that speculators profit from time series momentum at the expense of hedgers.     

Trend-following trading strategies in commodity futures: A re-examination

This paper examines the performance of trend-following trading strategies in commodity futures markets using a monthly dataset spanning 48 years and 28 markets. We find that all parameterizations of the dual moving average crossover and channel strategies that we implement yield positive mean excess returns net of transactions costs in at least 22 of the 28 markets. When we pool our results across markets, we show that all of the trading rules earn hugely significant positive returns that prevail over most subperiods of the data as well. These results are robust with respect to the set of commodities the trading rules are implemented with, distributional assumptions, data-mining adjustments and transactions costs, and help resolve divergent evidence in the extant literature regarding the performance of momentum and pure trend-following strategies that is otherwise difficult to explain.     

Volatility transmission in global financial markets

This paper considers the transmission of volatility in global foreign exchange, equity and bond markets. Using a multivariate GARCH framework which includes measures of realised volatility as explanatory variables, significant volatility and news spillovers are found to occur on the same trading day between Japan, Europe, and the United States. All markets exhibit significant degrees of asymmetry in terms of the transmission of volatility associated with good and bad news. There are also strong links between diffusive volatilities in all three markets, whereas jump activity is only important within the equity markets. The results of this paper deepen our understanding of how news and volatility are propagated through global financial markets.     

Profitability of momentum strategies in international markets: The role of business cycle variables and behavioural biases

The paper investigates whether business cycle variables and behavioural biases can explain the profitability of momentum trading in three major European markets. Unlike previous studies, the paper nests both risk-based and behavioural-based variables in a two-stage model specification in an attempt to explain momentum profits. The findings show that, although momentum profitability in European markets is unexplained by conditional asset pricing models, it is attributable to asset mispricing that systematically varies with global business conditions. In addition, behavioural variables do not appear to matter much. Thus risk factors, which are undetected thus far and are largely attributable to the business cycle, could explain the momentum payoffs in European stock markets.