Time Series Momentum in the US Stock Market: Empirical Evidence and Theoretical Implications

51 Pages Posted: 22 May 2020

See all articles by Valeriy Zakamulin

Valeriy Zakamulin

University of Agder - School of Business and Law

Javier Giner

University of La Laguna - Faculty of Economics, Business and Tourism

Date Written: April 26, 2020

Abstract

We start this paper by presenting compelling evidence of short-term momentum in the excess returns on the S&P Composite stock price index. For the first time ever, we assume that the excess returns follow an autoregressive process of order p, AR(p), and evaluate the parameters of this process. Armed with a fairly accurate knowledge of the momentum generating process, we continue this paper by providing a number of important theoretical implications. First, we present analytical results on the profitability of long-only and long-short time-series momentum (TSMOM) strategies. Our results suggest that the long-only TSMOM strategy is profitable, while the long-short one is not. We find that over multiple periods the risk profile of the long-only TSMOM strategy resembles the risk profile of a portfolio insurance strategy. We estimate the power of the statistical test for superiority of the TSMOM strategy and find that the power is much below the acceptable level. Consequently, any empirical study tends not to reject the null hypothesis of no profitability of TSMOM strategy. Finally, we evaluate the precision of identification of the optimal number of lags in the TSMOM rule using a standard back-testing methodology and find that this precision is extremely poor. However, we demonstrate that the performance of the TSMOM rule is robust to the choice of the number of lags.

Keywords: technical trading rules, time series momentum, profitability, statistical power

JEL Classification: G12, G14, G17

Suggested Citation

Zakamulin, Valeriy and Giner, Javier, Time Series Momentum in the US Stock Market: Empirical Evidence and Theoretical Implications (April 26, 2020). Available at SSRN: https://ssrn.com/abstract=3585714 or http://dx.doi.org/10.2139/ssrn.3585714

Valeriy Zakamulin (Contact Author)

University of Agder - School of Business and Law ( email )

Service Box 422
Kristiansand, N-4604
Norway
+47 38141039 (Phone)

HOME PAGE: http://vzakamulin.weebly.com/

Javier Giner

University of La Laguna - Faculty of Economics, Business and Tourism ( email )

Camino La Hornera s/n
La Laguna, Tenerife, 38071
Spain
+34 922317102 (Phone)

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