Britain and the United States carried out a planned drill with leading global firms on Thursday to see how they would respond to a cyber incident in the financial sector.
The test focused on how the world's two biggest financial centers, New York and London, would cope with a cyberattack in terms of sharing information, communicating with the public and handling an incident.
"Confronting the cyber threat is a team effort that requires coordination at all levels. Today's exercise with our U.K. partners is an important step to ensure that we are doing all we can to share threat information, adopt best practices and support our collective resiliency," U.S. Treasury Secretary Jacob Lew said in a statement.
"We train and prepare for the threat of a financial cyber incident," added Britain's finance minister, George Osborne. "And we will continue to work with our partners in the U.S. to enhance our cyber cooperation."
Details of the simulation exercise weren't released.
In addition to Treasury, U.S. participants included: White House National Security Council, Department of Homeland Security, FBI, Secret Service, the Federal Reserve and the Securities and Exchange Commission as well as financial institutions and industry groups.
The test was announced earlier this year by British Prime Minister David Cameron and U.S. President Barack Obama in light of the interconnectedness of the global financial system.
U.S. financial institutions have already been targets of a major hack. Earlier this week, federal prosecutors filed charges against three men accused of orchestrating a massive 2014 cyberattack against JPMorgan Chase & Co. and other financial giants.