His Medco Energi International, which he founded in 1980, is expanding into Libya, Yemen, Tunisia. Family sold 20% stake to Mitsubishi in August for $352 million but still holds majority of shares. Arifin is now adviser; brother Hilmi is chief executive, sister Yanti active in philanthropy.
To compile this list we looked at shareholdings in publicly traded companies as well as in private company filings. For people with publicly traded fortunes net worths were calculated using current share prices and exchange rates. For privately held fortunes we estimated what they would be worth if public.