AB 539 Health care coverage: prior authorizations

What happened

Governor Newsom vetoed AB 539 on September 20, so its proposed prior-authorization validity rule did not become law. The signed veto message describes a requirement that approved authorizations for health care services requested by in-network providers remain valid for at least one year, or for the treating provider’s requested period when shorter. The Governor’s September 20 legislative update independently lists the veto. This closes the legislative proposal without establishing a new authorization-renewal obligation.

The Governor acknowledged the aim of reducing administrative burden but said the measure applied authorizations too broadly and would limit plans’ ability to reassess medical necessity when a member’s condition changes. His message raised concerns about overutilization, inappropriate continuation of services, unnecessary costs, and conflicts with clinical guidelines and utilization-management controls. These are the Governor’s stated reasons for withholding his signature, rather than findings about a particular plan’s practices. Existing authorization and continuity-of-care obligations require their own legal and operational assessment.

Why it matters

The veto removes the proposed one-year rule from implementation planning while leaving existing authorization duties and independent improvement work in place.

Sources

• AB 539 Health care coverage: prior authorizations, bill historyOfficial · California Legislature · 2026-09-03 · Source review 2026-09-10
• AB 539 Health care coverage: prior authorizations, current bill text (08/30/26 - Enrolled)Official · California Legislature · 2026-08-30 · Source review 2026-09-10
• Official retained source documentOfficial · Official issuing agency · Source review 2026-10-16
• Official retained source documentOfficial · Official issuing agency · Source review 2026-10-16