In short
Mini-GmbH is a colloquial name for the UG (haftungsbeschränkt). There is no separate legal form of this name.
Mini-GmbH explained
The name captures the essence: the UG is a GmbH to which the minimum share capital of €25,000 does not apply; mathematically, €1 per share is enough. It was introduced in 2008 with the GmbH reform as a German alternative to the British Limited. The term cannot be used as a legal form suffix: the company name must contain "Unternehmergesellschaft (haftungsbeschränkt)" or "UG (haftungsbeschränkt)" (Sec. 5a (1) GmbHG). To compensate for the low capital, the UG must put a quarter of its annual net profit into a reserve every year. If it increases its share capital to €25,000, the special rules no longer apply.
