Material signal is the disclosure threshold of signal access. The model distinguishes ordinary internal information from information that could reasonably change another participant’s decisions, safety, rights, resource access, or understanding of a consequential situation. A water authority discovering contamination, a hospital finding a serious treatment failure, a company running critical AI infrastructure finding a systemic risk, a government knowing a policy produces the opposite of its public claims — all material.
The reversed burden
Once information crosses that threshold, the burden of proof flips. Instead of a participant having to argue why should I be allowed to know?, the institution bears why is withholding this necessary? — which turns secrecy into an exceptional jurisdiction, not an ownership right, one that must name who authorized it, on what grounds, who reviewed it, and when it expires, so that no secret by default becomes secret forever. See Guaranteeing Signal Access.