AUSTIN, Texas--(BUSINESS WIRE)--Fitch Ratings has affirmed its 'AAA' rating on the Texas Permanent School Fund's (PSF) bond guarantee program. The Rating Outlook is Stable. SECURITY Local school district bonds approved under the program are guaranteed by the corpus and income of the PSF. By law, a school district must notify the Commissioner of Education at least five days before a maturity date if it will be unable to pay debt service. Funds would then be transferred from the appropriate PSF a