The turmoil in the banking system spread to Europe and continued in the U.S. over the weekend, as a major European bank was bailed out by a trio of governments, the U.K. was plotting the rescue of a British lender and an American financial titan sought a buyer.

The Netherlands, Belgium and Luxembourg agreed to inject €11.2bn ($16.37bn) into Fortis NV on Sunday, after France's BNP Paribas SA and Dutch financial firm ING Groep NV walked away from talks to acquire the company over the weekend. The rescue effort came after Fortis's shares came under heavy selling last week.