The offered shares are expected to come from the holdings of the subsidiary's two existing shareholders, United Internet and Warburg Pincus, with United Internet to retain a majority stake even after the IPO, Ionos said.

It did not give details on the target issue price or the number of shares to be offered.

A source familiar with the matter recently told Reuters that a valuation of up to 5 billion euros would be realistic.

(Reporting by Hakan Ersen, Writing by Rachel More, Editing by Miranda Murray)