The newly appointed commissioner of the Bureau of Internal Revenue is Sixto S. Esquivias IV. He is an alumnus of USTHS and hails from the Class of 1971.

Atty. Esquivias IV dedicated 27 years of his life in the practice of his profession. From his graduation at the Far Esatern University with a Bachelor of Schience in Accounting degree and a CPA license a year after, to obtaining a Bachelor of Laws degree in Ateneo de Manila, he was immmediately exposed to the grind of his legal profession.

He started as Revenue Examiner at the Bureau of Internal Revenue from 1977-1981, then as a Reviewer at the Office of the Deputy Commissioner in the same office, from 1981-1982. He then successfully pushed himself to attaining higher positions thereafter as Head Executive Assistant for two years, and for four years, as Asst. Chief, Assessment Branch of BIR. The promotion was fast for this man who is driven by personal desire to achieve excellence in his work. Five years later, he was named Deputy Commissioner, legal and Enforcement, BIR, a position he held for two years.

Prior to his appointment, he is Managing Partner to the law firm of Esquivias, Cruz, Conlu and Yabut. His appointment is indeed recognition of his honest and dedicated service.

Sixto IV received an Achievers Award from the USTHS during its Diamond Jubilee in 2003. All eleven (11) Esquivias siblings graduated from UST High School. These included five(5) boys all similarly named Sixto from the 3rd to the 7th. His six (6) other siblings are girls, most prominent of whom is Ms. Leebai Esquivias-Gamboa '78, Vice President of the UST High School Alumni Association, Inc.. They had eight (8) other cousins from the Esquivias clan who also graduated from USTHS.