The possible collapse of two asset-backed commercial paper (ABCP) conduits sponsored by Bank of Montreal has cast a shadow over a tentative deal reached in December to stabilise Canada’s C$33bn (US$33.5bn) market in non-bank commercial paper.

BMO’s shares sank almost 10 per cent late last week amid concerns that it faces further hefty writedowns on the two conduits, known as Apex Trust and Sitka Trust.