Texas Government Code - GOV'T § 1204.006. Maximum Interest Rate

(a) The maximum rate of interest for any issue or series of public securities, including an issue or series that is issued in exchange for property, labor, services, materials, or equipment under another law, is a net effective interest rate of 15 percent.

(b) Except as provided by Section 1204.007, a public agency may issue and sell any issue or series of its public securities at any price and bearing interest at any rate or rates determined by the agency's governing body that does not exceed the maximum rate under Subsection (a).