Barclays PLC (LSE:BARC), NatWest Group PLC (LSE:NWG), Lloyds Banking Group PLC (LSE:LLOY) and other UK banks have provided the National Court Agency with customer data as part of plans to tackle "dirty money" flowing through the company's economy.
The project, which is the largest of its kind in the world, is set to take on criminal gangs and money laundering, which is estimated to cost the economy some £350 billion every year.
It comes around a year after more than six banks, including Lloyds and NatWest, started a trial in which they provided law enforcement with information on client accounts.
The NCA's project went live in May and has already highlighted eight potential crime networks that may be manipulating the financial system.
Other lenders involved in the project include Santander, TSB, Metro Bank and Starling Bank.
Adrian Searle, director at the NCA, said: "The fundamental purpose is to bring together the collective efforts of law enforcement, government, regulators and the private sector to combat economic crime."