Abstract: The invention relates to a magnesium-based alloy and a semi-finished product produced therefrom with uniformly small grain size and high cold forming capability. In order to create a fine-grain billet from an ingot, the material of which is highly formable (deep-drawable) at increased temperature and at room temperature and has desirable corrosion properties, according to the invention a magnesium-based alloy (L1, L2) is provided, containing in % by weight zinc (Zn) more than 0.8, but less than 6.2, zirconium (Zr) traces, but less than 1.0, manganese (Mn) more than 0.04, but less than 0.6, calcium (Ca) more than 0.04, but less than 2.0, silicon (Si) traces, but less than 1.0, antimony (Sb) traces, but less than 0.5, silver (Ag) more than 0.1, but less than 2.0, the rest being magnesium and production-related contaminants.