Atol Compania Naviera S.A. was formed in 1975. It was a type-A holding company and the main company of Christina Onassis Group, that owned the majority of the shares of the other companies of the group.
Barbados Marine S.A. was formed in 1957. It was a type-C company mainly engaged in shipping and owner of the vessel Olympic Light. After 1975 Cramer Panama S.A. was the sole shareholder of the company. The company dissolved in 1982.
Barrow Holding Corporation was formed in 1986. It was a type-B company mainly acting as intermediate holding company. It belonged to Pinelands Marine Panama S.A. This new company was formed after the division of the Onassis assets and the restructuring of the companies to serve the needs of the Christina Onassis group, which was managed separately by OMSA and separately from the Alexander S. Onassis Foundation's companies.
Carlow Maritime Panama S.A. was formed in 1968. It was a type-C company mainly engaged in shipping and owner of the vessel Olympic Banner.After 1975 the company passed to the Christina Onassis Group of companies owned by ATOL and managed by OMSA. After 1999 the ownership of Christina Onassis Group of Companies passed to her daughter Athina Onassis. The management of the companies was still held, separately from the Alexander S. Onassis Foundation Companies, until 1999. The company was dissolved in 2000
Chester Navigation Company S.A. was formed in 1957. It was a type-C company mainly engaged in shipping and owner of the vessel Olympic Cloud.
Corona Navigation Company Panama S.A. was formed in 1968. It was a type-B (and type-C) company acting as intermediate holding company.
Corrientes Sociedad Maritima S.A. was formed in 1951. It was a type-C company mainly engaged in shipping and owner of the vessel Olympic Mariner.
Coventry Panama S.A. was formed in 1980. It was a type-B company mainly acting as intermediate holding company. In 1980 the company owns all the shares of Dover Marine Panama S.A.
Dahlgren S.A. was formed in 1980. The company was dissolved in 2007.
East Argolikos Investment Company Limited was formed in 1965. It was a type-C company, mainly engaged in real estate. After 1975 the company passed to the Christina Onassis Group of companies owned by ATOL and managed by OMSA. After 1999 the ownership of Christina Onassis Group of Companies passed to her daughter Athina Onassis. The management of the companies was still held, separately from the Alexander S. Onassis Foundation Companies, until 1999.