January Effect and Tax-loss Selling Hypothesis

Abstract

The January effect is one of the most documented calendar anomalies that exist in the stock market, and this anomaly directly challenges the Efficient Market Hypothesis (EMH) by stating that there exists a pattern in the stock market where a return can be gained. One popular explanation for the January Effect is the tax-loss selling hypothesis. This hypothesis states that investors sell off losing stocks in their portfolio at the end of the year to realize capital losses for tax purposes and subsequently repurchase them in January, which drives up the stock prices. Evidence from markets such as the United States, United Kingdom, Hong Kong, Singapore, and Thailand is collected and analyzed to show the effects of different tax structures and investor behaviors on the January Effect. The findings indicate that the tax-loss selling hypothesis substantially accounts for the January Effect found in the markets that levy capital gains tax. Other factors, such as investor sentiment and institutional behaviors also account for the existence of the anomaly for markets free of capital gains tax.