Calouste Gulbenkian left his oil fortune to a Lisbon foundation and his son Nubar about $2.5 million

Calouste Gulbenkian held shares in the Turkish Petroleum Company from 1912. The Red Line Agreement of 31 July 1928 confirmed his 5 percent of the company, renamed Iraq Petroleum in 1929. The stake made him "Mr Five Per Cent". In 1938 he put his oil interests into a Panamanian company that became Partex. He died in Lisbon on 20 July 1955, aged 86. Historian Jonathan Conlin puts his 1955 wealth at £201 million, excluding art. His will of 18 June 1953 left the residue and the art to a foundation in Portugal. The state approved its statutes on 18 July 1956, and José de Azeredo Perdigão became president. His son Nubar received about $2.5 million in cash and trust. Nubar had worked unpaid for his father. In 1939 the firm refused his $4.50 expense claim for a chicken lunch, and he sued his father for $10 million, then withdrew. Time reported that he was shut out of the foundation's management and later received an undisclosed settlement from it. A 1929 trust let trustees pay Nubar or anyone in whose house or employment he lived. The House of Lords upheld that clause in 1968 in Re Gulbenkian's Settlements. Nubar died in Cannes on 10 January 1972, worth $5 million to $6 million. In June 2019 the foundation sold Partex to Thailand's PTTEP for about $622 million. In 2026 the foundation and the collection are in Lisbon, and Gulbenkian's ashes are recorded at St Sarkis Church in London^†.