In English, a public company is a company whose shares can be freely traded by the public.
In German, a public company is a company that is owned to the government. Companies that are listed on the stock market are called "kotiert".
This could hint at a cultural difference, with the Germans more strongly identifying with the government ("if it belongs to the government, it belongs to everyone"), whereas the English speaking countries might tend to identify more strongly with the economy ("if everyone owns or at least could own some shares of it, it belongs to everyone").