When during the month is the best time to own equities to maximize stock market returns? Equity markets respond throughout the month to events such as earnings reports, economic news and political actions. They also respond to another event that is not as commonly followed, the month-end trade.

Thackray’s 2011 Investor’s Guide refers to the effect as “Super Seven Days”: The last four days of the month and the first three days of the following month typically yield higher returns than other periods during the month. Reasons for strength are month end “window dressing” by institutional investors and new monthly fund inflows into pensions and mutual funds that subsequently are invested into equity markets.

The month-end trade phenomenon is notable around Halloween.