Barclays was nearing an agreement to resolve a US and British investigation into its alleged currencies-rigging efforts, but it pulled out of settlement talks at the last minute because of complications involving New York’s banking regulator, according to people familiar with the matter.

As a result, when the UK's Financial Conduct Authority and the US Commodity Futures Trading Commission announced multi-bank settlements Wednesday morning, Barclay was not included. The news caught investors by surprise, sending shares in Barclays down 1.75% in morning trading.