A refusal by US oil companies including ExxonMobil and Chevron to disclose their US tax payments is undermining the international effort to fight corruption in natural resources industries worldwide, according to transparency campaign groups. The chairman of the Extractive Industries Transparency Initiative, whose participants include 51 governments and most major western companies, said it was “disappointing” that the largest US oil groups “did not provide the leadership expected from them”, in the latest sign that the 15-year-old initiative is under strain. The Trump administration withdrew the US from the initiative last November, even though it said at the time it continued to “value the EITI as a critical tool to promote transparency, increase competitiveness, and combat corruption around the world”. Participants in the EITI commit to disclosing how much companies are paying, and governments are receiving, for natural resources developments, on the grounds that increased visibility of the flows of money will reduce opportunities for corruption and improve accountability. Both Exxon and Chevron have disclosed their tax payments to other countries around the world but, like most other US companies, have chosen not to reveal their corporate tax payments to the US.