Commerzbank chief Bettina Orlopp shot down an invitation from Andrea Orcel to hold informal talks about a potential tie-up with UniCredit, and has instead insisted on receiving a written proposal before engaging, according to people familiar with the situation.

Commerzbank reiterated on Friday that it will not meet with UniCredit for formal discussions until it receives a specific proposal from the Italian bank, which has ruffled feathers in Berlin with its interest in a merger.