{"id":215753,"date":"2024-11-29T11:40:02","date_gmt":"2024-11-29T16:40:02","guid":{"rendered":"https:\/\/ibkrcampus.com\/campus\/?p=215753"},"modified":"2024-11-29T16:13:58","modified_gmt":"2024-11-29T21:13:58","slug":"calendar-anomalies-much-ado-about-nothing","status":"publish","type":"post","link":"https:\/\/www.interactivebrokers.com\/campus\/ibkr-quant-news\/calendar-anomalies-much-ado-about-nothing\/","title":{"rendered":"Calendar Anomalies, Much Ado About Nothing"},"content":{"rendered":"\n

The article “Calendar Anomalies, Much Ado About Nothing” first appeared on Alpha Architect<\/a> blog.<\/em><\/p>\n\n\n\n

An anomaly is a pattern in stock returns that deviates from what is expected based on established financial theories or models. These patterns can sometimes present opportunities for abnormal returns. However, they are often inconsistent and challenging to exploit. Many anomalies have achieved consensus and, thus, have been incorporated into factor-based models, including size, value, momentum, profitability, and investment. And mutual funds and ETFs have been developed that incorporate these factors. An exception is that despite calendar-based anomalies (such as day of the month, month of the year, \u201cSell in May and Go Away,\u201d and many more) having achieved much attention from academic researchers.<\/p>\n\n\n\n

For example, see the following articles:<\/p>\n\n\n\n

The Halloween Indicator, \u2018Sell in May and Go Away\u2019: Another Puzzle<\/a><\/p>\n\n\n\n

Are Seasonal Anomalies Real?<\/a><\/p>\n\n\n\n

An Anatomy of Calendar Effects<\/a><\/p>\n\n\n\n

Equity Returns at the Turn of the Month<\/a><\/p>\n\n\n\n

Do Seasonal Anomalies Still Work?<\/a><\/p>\n\n\n\n

There are no models that incorporate them, nor are there even any funds that attempt to exploit them.<\/p>\n\n\n\n

A plausible explanation for this failure is that calendar anomalies could result from statistical data snooping\u2014they suffer from look\u2011ahead and survivorship biases<\/a>. Another is that just because a statistical significance of a calendar anomaly exists does not mean that after implementation costs it will lead to abnormal portfolio performance\u2014statistical studies often ignore transactions and other implementation costs, let alone taxes. In other words, are calendar anomalies just an ado about nothing?<\/p>\n\n\n\n

New Research<\/strong><\/p>\n\n\n\n

To answer that question, Samveg Patel, author of the study, \u201cCalendar Anomalies: A Portfolio Approach<\/a>,\u201d published in the September 2024 issue of The Journal of Wealth Management, evaluated the calendar\u2011anomalies\u2011based active portfolio strategies using daily closing prices of the S&P 500 Total Return Index (TRI) and MSCI All Country World Index (ACWI). To test the calendar anomalies found in the literature from a statistical perspective, Patel applied a time\u2011series regression model with dummy variables for each day, date, and month and constructed portfolios based on equal amounts of investments on a particular day, date, or month. His sample covered the period from inception (1988 for S&P 500 TRI and 2001 for MSCI ACWI) to 2023. Following are his key findings:<\/p>\n\n\n\n