Institutional bondholders in ProSiebenSat.1, the majority-owned subsidiary of Germany-based KirchMedia, are considering defaulting their debt in a bid to scupper the company's proposed merger with its debt-laden parent.

The Noteholders' Committee, a group of leading credit and bond fund managers in Europe and the US that holds more than 25% of ProSiebenSat.1's debt, has appointed international law firm Norton Rose to investigate whether investors can require early repayment from ProSiebenSat.1 based on the terms of the notes.