The power to tax corporations and corporate property shall not be surrendered or suspended by act of the Legislature, by any contract or grant to which the State shall be a party.
Tex. Const. art. 8, § 4, under Taxation and Revenue.
Tex. Const. art. 8, § 4
SURRENDER OR SUSPENSION OF TAXING POWER
The power to tax corporations and corporate property shall not be surrendered or suspended by act of the Legislature, by any contract or grant to which the State shall be a party.