TX SB266

Changes documentation requirements for taxpayers from "contemporaneous" records to "sufficient" records when substantiating tax claims in administrative or judicial proceedings, allowing invoices, vouchers, checks, shipping records, contracts, and electronically stored images

Creates a new process allowing taxpayers who conduct managed audits under Sections 151.0231 or 201.3021 to bypass the redetermination process and file suit directly in district court within 60 days after receiving audit results, provided they submit a written notice of intent specifying disputed facts, legal bases, and amounts

Abates the 10% penalty for unpaid tax determinations when a taxpayer files a timely suit disputing managed audit results; the penalty only applies if the final judgment amount remains unpaid after 20 days

Requires suits disputing managed audit results to be filed against both the comptroller and attorney general in district court, with automatic enjoinment of collection on disputed amounts during litigation while allowing the state to assert tax liens or require security in the form of cash deposits, surety bonds, or letters of credit

Applies to managed audits in progress and administrative or judicial proceedings pending or filed on or after the effective date, taking effect immediately with two-thirds legislative vote or September 1, 2025