HB 423 amends Subchapter D, Chapter 11 of the Education Code by adding Section 11.187, which prohibits school district boards of trustees from entering into certain contracts. Specifically, the bill prevents school district boards from contracting with any trustee of a school district or with a company in which a trustee holds an ownership interest and stands to gain financially from the contract. The bill requires trustees to disclose any such ownership interests to the board and the Texas Education Agency (TEA). Contracts entered into in violation of these provisions are deemed void. An exception is provided for contracts governed by Section 45.204 of the Education Code, relating to the issuance of bonds and related contracts. The bill directs the commissioner of education to adopt implementing rules by December 1, 2025, with the law taking effect on September 1, 2025.