The Royal Bank of Scotland has been fined 100m dollars by US regulators for illegal transactions with Iran, Sudan, Burma and Cuba.The fine for the violations against US sanctions, which took place between 2005 to 2009, follows a 2010 internal investigation by RBS into its historical US dollar payment processes and controls. RBS found that bank procedures removed location information on payments made to US financial institutions from other countries including Iran and Cuba. The bank's review was passed on to US authorities. The US Treasury Department said the state-backed lender instructed employees to list the name of the Iranian financial institution rather than its identifying codes on wire transfers.RBS said it "acknowledges and deeply regrets these failings" following the settlement with the Federal Reserve, the New York State Department of Financial Services and the Office of Foreign Assets Control."RBS embarked on an extensive remediation plan to address the shortcomings identified in its investigation," the bank said in a statement after the UK market closed on Wednesday.The news came the same day as the bank announced Financial Director Nathan Bostock would resign just 10 weeks into the position. Bostock is leaving to join the UK arm of Spanish bank Santander as Deputy Chief Executive. His departure comes at a critical time as the bank undergoes a comprehensive review and major overhaul in preparation for its return to privatisation. RBS has also recently had to deal with a series of issues, including IT problems which on 'Cyber Monday' caused hundreds of thousands of the bank's customers unable to access their accounts after a computer systems failure.RD