Share deal and asset deal are two different ways by which a company can be transferred to a new owner.
Object of purchase - purchase of shares of a company
A share deal is the acquisition of a company or a share of it through the purchase of shares. Either all shares in a limited liability company or stock corporation or only part of them are acquired, hence a majority or minority thereof. The purpose of this kind of transaction is the purchase of the company’s shares, but not its assets.
The share deal does not change the legal entity of the company: the purchaser merely moves into the position of the previous shareholders and gains influence on the formation of the will of the entity. This means that only the shareholder structure changes. The company remains with its previous company name.
Externally, the company, which is known on the market, remains unaffected and the completed share deal is often not even noticed, unless you have a look into the commercial register that is open to the public.
Contract partner
The contract partner of the acquirer is not the company, being the subject of the share deal, but the individual shareholders, since in a share deal the shareholders sell their shareholdings.
Liability
In the case of corporate legal entities (GmbH/AG) the acquirer of the shares is generally not liable for potential debts of the withdrawing shareholder(s), because only the corporate assets are liable for its debts.
In the case of partnerships (= a non-corporate legal entity), however, the newly joining partner is personally liable as a general partner in a general partnership (Offene Gesellschaft=OG), or up to the capital paid into the company in a limited partnership (Kommanditgesellschaft=KG).
In the case of a sole proprietorship (Einzelunternehmer) the company owner is a natural person. Hence, the company is not operated in the form of a corporate legal entity such as a GmbH or AG (stock company) nor as a general partnership (Offene Gesellschaft=OG) nor as a limited partnership (Kommanditgesellschaft=KG). A share deal is not possible since the sole proprietorship is not a legal entity and therefore no company shares exist. Only an asset deal can be considered (see under 2).