Governments are required under EITI's 2019 standards to disclose volumes received and sold as well as revenues from any oil, gas or mining-related deal, but under new guidelines unveiled by EITI on Monday, companies will be "encouraged" to do the same.
EITI said the requirements "enable stakeholders to form a more complete picture of the terms of sale of mining, oil and gas resource".
The body said reporting "provides companies with the opportunity to contextualise and complement information being disclosed by state and SOE [state-owned enterprise] counterparts through the EITI".
"Disclosures on payments related to oil, gas and mineral purchases from governments also allow buying companies to demonstrate their financial contribution to the economies of the countries from which they purchase commodities, which often constitutes an important source of government revenue," it said.
EITI added improved transparency "may also facilitate access to capital from financial institutions, notably in light of the growing importance within the investor's community of Environment, Social and Governance criteria, as well as the emergence of sustainability-linked financing schemes".
Commodity trading firms including Glencore, Gunvor and Trafigura are already disclosing their transactions around oil and mining where states or SOEs are concerned, EITI said.