UBS today took a critical move to offload US residential mortgage-backed securities holdings, on which it has written down billions of dollars, lending over $11bn (€7.1bn) to help finance a distressed fund's purchase of $15bn of debt from the Swiss bank.

The Swiss bank said this morning that it would lend the money to BlackRock, a US fund manager, to finance the dea. It had been reported to be in talks with BlackRock about a potential deal but the bank confirmed the sale of the portfolio today.