ANZ and Macquarie Bank will have to hold extra reserves with the central bank of up to US$300 million (A$250 million) after an investigation by the Monetary Authority of Singapore found the two Australian banks were linked to "attempts to inappropriately influence [interest rate] benchmarks."MAS undertook a year-long review of Singapore dollar interest-rate benchmarks - the Singapore Interbank Offered Rates (Sibor) and Swap Offered Rates (SOR) - as well as the Foreign Exchange spot contract for the period from 2007 to 2011.The inquiry looked for systemic flaws with the Sibor rate in the wake of the controversies over the setting of the London Interbank Offered Rate benchmark.The MAS censured 20 banks for "deficiencies in governance, risk management, internal controls and surveillance systems."The Singapore bank regulator also directed the banks "to adopt measures to address deficiencies," it said.In addition they must "appoint [an] independent party to ensure robustness of remedial measures,"The banks are required to report their progress to MAS on a quarterly basis.The MAS included Macquarie in the censure even though it is not a contributing bank to the setting of benchmark rates, which are administered by the Association of Banks in Singapore. The banks must place the additional statutory reserves with MAS at zero interest for a period of one year, which may be extended."Based on the available information and evidence, no criminal offence under current Singapore law appears to have been committed," MAS said.The MAS will, however, introduce specific criminal and civil sanctions for manipulation of any financial benchmark.The MAS said its sanctions were "calibrated according to the severity of attempts by traders in these banks to inappropriately influence financial benchmarks."ANZ and Macquarie are lesser offenders, based on the level of additional reserves they must find.ANZ said in a statement that it had "identified certain inappropriate communications and behaviour that contravened ANZ's code of conduct. No-one has been dismissed, however appropriate disciplinary action has been taken with a small number of staff."ING, Royal Bank of Scotland and UBS must all find additional reserves of up to US$1.2 billion - four times the levy imposed on ANZ and Macquarie.Other banks sanctioned include Bank of America, BNP Paribas, and Oversea-Chinese Banking Corp.