Allianz and Commerzbank have joined forces with a view to a possible bid for Deutsche Postbank, the country’s largest retail bank, potentially kick-starting the long-awaited reshaping of Germany’s fragmented financial industry.

Allianz, the insurance group that owns Dresdner, Germany’s third-largest bank, has held detailed discussions with Commerzbank about making a combined offer for Postbank, which is expected to be put up for sale by Deutsche Post, its majority owner.