Slaughter and May best friend Hengeler Mueller has secured a plum role advising German conglomerate Siemens on the initial public offering (IPO) of its €7bn (£4.7bn) car parts unit.

The Munich-based company has begun gearing up for the flotation of Siemens VDO, which would be the largest German float since Deutsche Telekom's float in 1996.

Siemens has stated its intention to float 25%-50% of the automotive company, although it is also considering a sale.

Siemens is a longstanding Hengeler client, although the multinational has been known to use Freshfields Bruckhaus Deringer for advice as well.

Recent notable Siemens deals include its A4.2bn (£2.8bn) acquisition of German drug maker Bayer's medical testing arm last July. On that occasion, Freshfields Munich corporate partners Axel Epe and Barbara Keil advised Siemens, while Hengeler acted for the target's owner, with M&A partners Matthias Hentzen, Christian Moeller and Jochen Vetter.

The mandate comes 18 months after Hengeler set up shop in Siemens' hometown, Munich.

The elite German firm launched the office by relocating M&A partners Gerhard Lang, Achim Herfs and Wolfgang Grobecker to the Bavarian capital, before adding respected Freshfields corporate partner Hans-Joerg Ziegenhain in January last year.