What is an Aktiengesellschaft?
Beside GmbH, the Geman speaking countries also reglementate the Aktiengesellschaft companies.
The German term Aktiengesellschaft (short: AG) means a corporation which is limited by shares, i.e., owned by shareholders. It may be traded on the stock market. The term is used in Germany, Austria and Switzerland.
Aktien means shares, and Gesellschaft means business association in this context, therefore is the equivalent of corporation from the USA.
The legal basis of the AG is, in Germany and Austria, the respective Aktiengesetz (abbr. AktG), in Switzerland a part of the Obligationenrecht (OR). As the law requires all corporations to specify their legal form (which gives the limitation of liability) in the name, all German and Austrian stock corporations bear Aktiengesellschaft or AG as part (usually suffix) of their name.
When a corporation is started, it often must collect a lot of money to pay for startup costs, and banks provide only a limited amount, especially if it is unknown whether that corporation is going to earn enough money to repay all the loans plus interest on time. However, some members of the public will take a risk and provide money in exchange for a piece of paper, or just a book entry, that can be sold to others on the stock market, and that has a value that fluctuates, depending on, for example, whether the shares concerned will pay dividends, and if so, how much per year, or what percentage of the current price of the shares.