Two men who were arrested in Coleraine and Ballymoney on Tuesday by the organised crime branch have been released on bail. A third man was also arrested but later released on Tuesday.
The three were arrested by detectives investigating mortgage fraud, money laundering and tax evasion, thought to run into millions of pounds.
The enquiry includes £3m mortgage fraud relating to 25 properties as well as income tax evasion and capital gains tax evasion.