There is also a market adage about “Beware the Ides of March” from the Stock Trader’s Almanac, as the middle of the month can bring added volatility leading into the back half of the month. The recent bias over the past roughly 20 years or so has brought lows during the middle of the month for the market to rally in the latter part of March.
“Beware the Ides of March!” Some may be familiar with the phrase as a warning to Julius Ceasar to beware the Ides of March as potential harm may come to him before his very assassination in the middle of March (the Roman calendar referred to the middle of each month as the Ides). There are numerous other mythological and theological references to the Ides of March as a time for celebrations and festivals, but also as a time when there is typically a full moon, which can be perceived by some who follow astrology as a period in a month when things can get a bit wacky. Barring the aforementioned references, there is also a market adage about “Beware the Ides of March” from the Stock Trader’s Almanac, as the middle of the month can bring added volatility leading into the back half of the month.
The first table below highlights the average performance of the S&P 500 Index (SPX) during the first and second half of March since 1957, along with the full months and the year-to-date performance. Through the first roughly 50 years of study, the front half of the month outperformed the back half on average. But as a recent note from Jeff Hirsch (the editor of the Stock Trader’s Almanac) noted, the recent bias over the past roughly 20 years or so has brought lows during the middle of the month for the market to rally in the latter part of March.
The second table expands on this study and shows the performance of SPX week by week through the month of March. On average, the second and fourth weeks of the month tend to produce the best performance, while the first week tends to be muted and the third week brings about downside action. Below highlights some of the performance tendency observed from the week-by-week performance data.
Going back to the beginning of 1957, there have been 22 instances of the first two weeks of March yielding positive performance when examining week by week data. On average, when the first two weeks have been positive, the back half of the month has been down roughly 60% of the time and down 58 basis points on average.
Examining the data when only one of the first two weeks is positive reveals that the performance has been better in the back half of the month, on average when the index is negative the first week and positive the second. When the first week of March has been positive and the second week negative, returns in the back half of the month are down 5 basis points on average. Meanwhile, when the first week of March is negative and the second week positive, returns in the back half of the month are up 1.17% on average.
What is intriguing about March 2026 is that Friday’s (3/13) close marks a third year in a row that action during the first two weeks of March was negative when examining week-by-week performance. The first full week of the month this year witnessed SPX fall more than 2% (2/27 – 3/6), while this week’s action saw the index shed another 1.6%. Looking back to March 1957, SPX has been negative during the first two weeks when examining week by week returns on 13 prior instances, with over 60% of those occurring since 2001. During prior occurrences, SPX has generally seen a rebound during the two weeks following when examining week-by-week performance and a two-week roll. Three years – 1980, 2005, and 2025 – were the only years resulting in additional downside to close out the month of March. 76% of the 13 instances have resulted in positive returns in the final two-week stretch of March with SPX registering an average return of 1.11%.
With the third week of the month upcoming, investors will see if U.S. equity indices can find some footing for the back half of the month. Years like 1970, 2001, and 2004 witnessed negative action during the third week, continuing downside from the prior weeks, before those three years saw a notable rebound during the fourth week to finish the month out positively. As we are near the end of the first quarter of 2026, March’s performance has brought many indices into negative territory on a year-to-date basis, and the final two weeks could very well determine if the quarter is negative or positive. Additionally, with domestic equities falling to the third position and the recent shake up to the top of the NDW DALI Rankings, users will see if a potential rebound in the back half of March may provide a catalyst for a bounce up in rankings for the asset class. Closing out the month on a negative note could provide additional fodder for the recent leadership change to the top of the DALI asset class rankings.
