It maybe counterintuitive but one thing to understand in the shipping industry. Ship liner does not mean ship owner. An example of a ship liner would be Evergreen. Maersk, MSC, CMA CGN, COSCO, ONE, MOL, and so on. It would be a surprise to people that these liners do not necessarily own the ships that sail under their colors. They are leased from shipowners or a consortium of shipowners. For example, the infamous Ever Given which blocked the Suez Canal. While it is an Evergreen ship, which is a Taiwanese company, the ship is owned by a Japanese financial institution. The institution is the one that financed and made the build order to a Japanese shipyard, and leased the ship to Evergreen. Usually there is a consortium of shipowners that supply leasing agreements to a shipping line. For instance there is a class of ship that is run by a shipping line, with an X number of vessels, these vessels can have different owners each. Thus while Greece does not have a shipping line in the same size and caliber of Maersk, MSC, and CMA CGN, any number of vessels by these shipping lines are owned by Greek tycoons or institutions, which are leased to the shipping lines. One has to remember that many of these ships are bought and ordered from Chinese shipyards, or they served the Maritime Belt route, the artery for China's global exports.
In the case of COSCO, while it is a state owned shipping line, various vessels may be owned by other institutions, usually state owned banks, financial institutions and even local governments.