Tex. Natural Resources Code § 11.086

(a) Information relating to the development, location, purchase price, or sale price of real property developed, purchased, or sold by or for the School Land Board, Veterans' Land Board, land office, or commissioner under authority granted by this code, including a contract provision related to the development, purchase, or sale of the property, is confidential and exempt from disclosure under Chapter 552, Government Code, until all deeds for the property that are applicable to the transaction or series of related transactions are executed and until all substantive performance or executory requirements of applicable contracts have been satisfied. Information that is confidential and exempted from disclosure under this subsection includes an appraisal, completed report, evaluation, or investigation conducted for the purpose of locating or determining the purchase or sale price of the property, or any report prepared in anticipation of developing, purchasing, or selling real property.

(b) Information that is confidential and excluded from disclosure under Subsection (a) is not subject to a subpoena directed to the School Land Board, Veterans' Land Board, land office, commissioner, attorney general, or governor.