As part of the deal, the Zurich, Switzerland-based bank would sell BlackRock a portfolio of subprime mortgages valued at just over $20 billion for a discounted price of $15 billion, according to the published reports.

The deal with BlackRock comes on the same day that Switzerland’s largest bank reported a first-quarter loss of $11 billion due in large part to $19 billion in write-downs tied to the struggling U.S. real estate market.

A spokeswoman for BlackRock confirmed that UBS had announced the deal in principle, but would not say if the portfolio had been purchased at a discount rate.