After completing the purchase of another company, do buyers trail the average company in the second and third months?
Study 62 · No reading (stopped by its own checks) · recorded 21 October 2026 · answer: Not settled · full paper with figures
The question
Buyers' shares are known to lag in the years after a purchase; this asks about a shorter window. We sum each buyer's daily return less the average for companies priced at five or more over sessions 22 to 63 after completion, and ask whether a shortfall is larger for less traded buyers and after a rise on the completion day.
Rules fixed before the result
Fixed before any outcome: at least 120 purchases by 90 companies over 16 calendar quarters, and power to detect a shortfall of 2.5 percentage points. The plain average decided if a power check on ordinary spans of the same companies allowed it; otherwise the clipped average, which sets each tail's most extreme twentieth to its edge, could decide only if its false-alarm rate on other companies over the same days lay within 2.5% to 7.5%. Otherwise the study stopped.
Data and method
Each purchase is dated at the completion our records give, from 2018 to 2022 in our development data, and kept if the buyer was priced at five or more in the market's own currency the day before. The measure was the buyer's daily return less the average for companies priced at five or more the day before, summed over sessions 22 to 63, not a holding-period return. Its precision was estimated before any outcome was read, on ordinary 42-session spans.
The answer
Not measured: the study stopped at its check of statistical power, before computing any buyer's return after a purchase. The plan allowed an answer only if the plain average of the summed gaps, or failing that the clipped average, could detect a shortfall of 2.5 percentage points over the 42 sessions; neither could, so by its own rule the study stopped there, and nothing was measured on the less traded buyers, the completion-day rise or the first week either. The question is answered neither yes nor no, and a shortfall of that size or larger is neither shown nor ruled out. The plan had expected a stop of this kind as its likeliest outcome, with low confidence, and gave any stop a chance of 0.35.
What it changes
No plan changed. The earlier verdict that closed this line of work stands as written and the line stays closed; this study was its one reopening, asking about a shorter window and a different comparison than the earlier year-long study, and the verdict would have changed only with a shortfall shown at the size tested.
What remains uncertain
Nothing after a purchase was measured, so neither a shortfall nor its absence is shown. The years 2018 to 2022 were used by earlier studies of these purchases, so even a measured answer would have been a check within our development data, not a test on fresh data. Deal terms were not held, the average company is not matched on size, and purchases on nearby dates share market moves that grouping by calendar quarter only partly captures.