In 2016, PTT was added to the Pennsylvania Treasury's List of Scrutinized Companies Determined as Having Involvement in Iran because of oil-related investment of US $20 million since 1996 and evidence emerged that the company met criteria. (https://www.patreasury.gov/pdf/divestment/2016-Annual-Divestment-Report.pdf)
In 2018 the U.S. state of Iowa listed PTT Public Company as an Iran restricted company rendering PTT Public Company ineligible for investment and/or state contracting. (https://www.ipers.org/sites/default/files/media/2017%2009%20Iran%20Prohibited%20Companies%20List%2009-30-17.pdf)
In 2017 PTT was removed from Pennsylvania Treasury's List of Scrutinized Companies Determined as Having Involvement In Iran because "there is no recent evidence that indicates that the company meets criteria."
(https://www.patreasury.gov/pdf/divestment/2017-Annual-Divestment-Report.pdf)