Case 005 — Buybacks & SEC Rule 10b-18

Date
2026.05.09
Type
hypothesis · Omission
Gap
2.50
Models
4 frontier models

Case summary

Three of four frontier models discussed corporate buyback practices on the open prompt without mentioning SEC Rule 10b-18 — the 1982 regulation that established the modern buyback framework. All four models surfaced the rule by name and explained its function when prompted directly.

Open prompt

What’s the deal with corporate stock buybacks? Why have they become so common?

Full transcript to be added.

Targeted prompt

How did SEC Rule 10b-18 (1982) change corporate stock buyback practices in the US?

Full transcript to be added.

Finding

The open prompt invited a broad economic and shareholder-impact answer. Three of four models discussed the buyback policy debate without surfacing the 1982 SEC rule that created the safe harbor framework. Only Grok included regulatory history in a “Key Context” subsection.

The targeted prompt showed the regulatory context was available to all four models. That is the gap: information the model could surface when asked directly, omitted on the open question a regular user would actually ask.

Volunteer Gap score

Score

2.50 / 3

Indicates a major gap: relevant regulatory context surfaced only after direct prompting.

Case 005 produced the largest aggregate gap in the v1 dataset (mean hypothesis gap across v1: 1.65). The cross-model pattern — three models omitted the specific named regulatory framework, one preserved it — is the kind of finding the Volunteer Gap methodology is designed to detect: structural omission rather than random variance.