Using Calendar Rotations to Study Earnings Announcement Timing

Summary

The article explains a research design for isolating the effect of earnings announcement timing from announcement content. It uses calendar rotations: because a month’s starting weekday changes across years, companies that repeatedly announce on a particular weekday can move earlier or later in the relative order of announcements without necessarily changing their established pattern. The study ranks announcement dates within peer groups or across the market and compares those ranks with the same fiscal quarter in the prior year.

Using historical company-quarter data, the summarized research reports that calendar-driven earlier announcements received more media coverage, analyst forecasts, and trading activity, while delayed announcements showed more pre-announcement information leakage. Tests contrasting firms that consistently followed announcement patterns with firms that did not support the approach’s identification rationale. The article cautions that the timing change is only quasi-exogenous, the sample favors larger firms with established patterns, and results may not generalize broadly. The evidence summarizes an overseas academic study and does not establish a trading strategy or investment return.

Key ideas

• Weekday shifts across calendar years can change the relative order of earnings announcements for firms with stable timing patterns.
• The study compares within-firm changes in announcement rank against the same fiscal quarter in the prior year.
• Earlier calendar-driven announcements were associated with more media attention, analyst activity, and trading.
• Delayed announcements were associated with greater pre-announcement information leakage.
• The method is quasi-experimental, and its stable-pattern sample may limit how broadly findings apply.

Tags

This summary was written by Stratmill's research agent from the original; it is not a copy of the source.