Does the year-long shortfall after a priced prospectus appear in drug and biotechnology companies and in other industries alike?
Study 52 · Changed a rule or plan · recorded 13 October 2026 · answer: Yes · full paper with figures
The question
Study forty-seven found that shares of companies filing a priced prospectus trailed comparable companies of the same industry and similar trading size over the year after the sale, in each kind of sale and period. We ask whether the shortfall holds in drug and biotechnology companies (the industry code beginning 28), 835 of 2,190 sales, and in other industries.
Rules fixed before the result
Fixed in advance: each group needed 400 sales by 150 companies and 60 per period. A group trails when its 95% range lies wholly below zero; both trailing reads yes; one alone carries it only if the other's range stays above a 0.08 shortfall and the difference's range excludes zero. Had a year range exceeded its limit, 0.28 for drug and biotechnology or 0.22 for the rest, the medians, the typical sale's figure, would have decided instead of the means.
Data and method
We rebuilt the earlier study's 2,190 sales by 745 companies unchanged and split them by industry code, each company compared with five comparable companies of the same industry and similar trading size. Ranges come from resampling whole companies 2,000 times with the earlier study's own draws, which reproduced its overall figures exactly, so both groups and their difference share one set of draws. The same companies' ordinary dates, away from any sale, were split the same way.
The answer
Yes. Over the year after the sale, in growth of wealth on the logarithmic scale, drug and biotechnology companies trailed their comparable companies by 0.22 (95% range 0.15 to 0.30) and the other industries by 0.26 (range 0.19 to 0.35); the difference between the groups ran from drug and biotechnology 0.07 deeper to 0.15 shallower, so larger gaps are excluded and smaller ones remain possible. Over the month both trailed, by 4.7 percentage points (range 2.8 to 6.6) and by 4.2 (range 3.0 to 5.4). On the same companies' ordinary dates neither group showed a shortfall over the year (ranges 0.10 below to 0.03 above, and 0.03 below to 0.04 above). In 2017-2019 the drug and biotechnology companies' shortfall over the year was measured but not shown, its range not lying wholly below zero.
What it changes
By the rule fixed in advance, the earlier finding stands as general across industries: the shortfall is not confined to drug and biotechnology companies. Counting a company's recent priced prospectuses as a warning sign is to be proposed as kept across industries, with the limitation that in 2017-2019 the drug and biotechnology companies' shortfall was measured but not shown, its range not wholly below zero, and this line of study rests until the size of each sale can be measured.
What remains uncertain
These sales were studied before (studies forty-five, forty-six and forty-seven), and their overall, kind and period figures were published before this plan; only the industry split is new. The difference between the groups is imprecise: drug and biotechnology could be up to 0.07 deeper or 0.15 shallower. Different companies' sales on the same dates share market and industry shocks that resampling whole companies does not treat, and the industry is each company's current code, not its code at the sale.
How it was made
Run took 65 minutes; independent code review: approve; the recorded calculation reruns to the same result.
Fingerprints
plan 6d79d7ace789bfd3620edc190320b62547f1bf04ec83862c27bf03541ec2e80b result ae79b15e2be9986f6fbd9484f21ddefec6565975f70a95b1b3605dde1d5f23af
Exploratory work on development data; not a performance claim.