Investment banks advising chemicals giant Dow Chemical and takeover target Rohm & Haas could stand to miss out on around $100m (€78m) in fees if the deal collapses, despite spending six months working on the tie-up between the US rivals.

Dow Chemical's decision this week to not close on the transaction 24-hours before it was due to complete has left the five mandated banks at risk of being paid just a fraction of the total fee pot available. Advisers are paid the bulk of their fees on successful delivery of deals.