Registered merchant (eingetragener Kaufmann, e.K.)
Also: e.K., e.Kfm., e.Kfr., eingetragener Kaufmann, eingetragene Kauffrau, sole trader in the commercial register
In short
A registered merchant is a sole proprietor whose business name is entered in division A of the commercial register and who uses a suffix such as "e.K.", "e.Kfm." or "e.Kfr.". Like every sole proprietor, they are liable without limit with their private assets.
Registered merchant (eingetragener Kaufmann, e.K.) explained
Registration is mandatory as soon as the business, by its nature or scope, requires a commercially organised operation (Sec. 1 (2), Sec. 29 HGB). Smaller traders may register voluntarily (Sec. 2 HGB). With registration, the Commercial Code applies: the owner may also use a descriptive or invented business name, must state the business name, suffix, place of business, register court and register number on business letters (Sec. 37a HGB) and can grant Prokura. A registered merchant only needs books and a balance sheet above the thresholds of €800,000 turnover or €80,000 annual profit (Sec. 241a HGB); below that, cash-basis accounting is sufficient.