Regulatory Bodies
OECD organization's guidelines on international taxation, widely adopted by national tax authorities.
The OECD (Organisation for Economic Co-operation and Development) publishes guidelines widely followed by tax authorities — Transfer Pricing Guidelines, BEPS Action Plan, Pillar 1/2. For mileage reimbursement in multinational groups, country-to-country standardization follows the "arm's length" principle recommended by the OECD. Site: oecd.org.