Credit Suisse shares fell as high as 65% Monday morning after UBS, the rival bank to Credit Suisse, agreed to take over the Swiss bank at a steep discount.

Credit Suisse shares CSGN fell -59.73% CS -6.94% mainly due to the 59% discount it accepted in the deal originally valued at 3 billion francs. However, the 14% slide UBS shares UBSG after the transaction was announced, -4.56% UBS -5.50%.

The Euro Stoxx bank index HTML7E, -1.47% , that doesn’t include UBS and Credit Suisse, fell by 4%.

One of the concerns that resulted from the deal is that the Swiss government reduced the value of AT1 bonds to zero. These bonds, also known as contingent convertible bonds (CoCos), have been a major funding source for European banks.

The Invesco AT1 capital bond ETF fell 14%