SB 53 — California Transparency in Frontier Artificial Intelligence Act (TFAIA)

Summary

California SB 53, the Transparency in Frontier Artificial Intelligence Act, applies to developers of frontier models (foundation models trained with more than 10^26 operations). Large frontier developers, those with annual revenue above $500 million including affiliates, must publish a frontier AI framework describing how they assess and mitigate catastrophic risk and secure model weights. Developers must publish transparency reports when they release new or substantially modified frontier models, and the act adds critical safety incident reporting and whistleblower protections. Civil penalties of up to $1 million per violation are enforced by the Attorney General. Governor Newsom signed it on September 29, 2025; it took effect on January 1, 2026.

Key dates

1. September 29, 2025Enacted
2. January 1, 2026Takes effect
3. October 16, 2026Checked against sources
4. October 21, 2026Checked against sources

Developments are added when the record is reviewed. Next review: October 16, 2027.

Evidence

Each passage is quoted from its source. The quoted passages are re-checked against the live pages every month.

1. Governor Newsom today signed into law Senate Bill 53, the Transparency in Frontier Artificial Intelligence Act (TFAIA), authored by Senator Scott Wiener (D-San Francisco)

   Supports: Bill number, name and signing (release dated September 29, 2025)

   Governor Newsom signs SB 53, advancing California's world-leading artificial intelligence industry Office of the Governor of California Primary source

2. Developers who are not in compliance with the law when it takes effect in January 2026 face civil penalties of up to $1,000,000 per violation, enforced by the California Attorney General.

   Supports: Effective date, penalty, enforcement

   The law imposes additional transparency and accountability requirements on "large frontier developers" whose annual revenue, including affiliates, exceeded $500,000,000 in the preceding calendar year.

   Supports: Revenue threshold for large frontier developers

   Transparency in Frontier Artificial Intelligence Act (SB-53): California Requires New Standardized AI Safety Disclosures WilmerHale Reporting or analysis

3. SB 53 (Wiener): Requires large AI developers to maintain documented risk-mitigation strategies

   Supports: Listed among laws taking effect in 2026

   New in 2026: California laws taking effect in the new year Office of the Governor of California Primary source