Commonwealth Bank's alleged rate manipulation of bank bill swap rates in 2012 could have delivered a revenue windfall running into at least the tens of millions of dollars, based on modelling submitted to the Federal Court by ASIC.The court yesterday allowed media outlets to access eleven documents filed by the Australian Securities and Investments Commission in the case it has brought against the country's largest bank over alleged unconscionable conduct in the setting of bank bill swap rates.One of the documents (known as Schedule I) contains allegations of CBA treasury employees sharing their trading intentions and sensitive information about BBSW positions to staff employed in other parts of the bank.ASIC included more than 80 transcripts of emails and taped phone conversations to support its claim that CBA staff regularly shared BBSW-related information over a ten-year period.ASIC alleges that the communications reveal attempts by treasury staff and swap traders to enhance the bank's positions on BBSW-referenced financial products.In one email sent in January 2012 senior treasury dealer Mark Hulme seeks information from senior swaps dealers in the markets division.The email read: "Can you confirm your BBSW positions so we can avoid any days where u may need high sets. Also could you send up your rateset ladder for 1, 3 and 6 BBSW for the next 3 months."A CBA spokesman said the bank would dispute the allegations."The Commonwealth Bank disputes the allegations made by ASIC as we do not believe our employees have engaged in unlawful conduct, nor have they done anything that would have adversely impacted the efficiency and integrity of financial markets as alleged, or at all," the bank spokesperson said.The regulator alleges in its statement of claim that the main victims of the alleged trading manipulations by bank staff were business customers who bought financial products from the CBA that had pricing linked to movements in the BBSW rate.The products included commercial loans, interest rate swaps, forward-rate agreements, inflation swaps and cross currency swaps.While ASIC did not give a total estimate of how much the alleged rate rigging practices added to the bank's revenue line in 2012, modelling undertaken by the regulator indicates that individual customers might have incurred extra costs running into the tens of thousands of dollars.In one of the schedules attached to the statement of claim, ASIC gives estimates of the impact of a five basis point movement in the BBSW rate on customers holding different financial products.According to ASIC, individual customers that entered Forward Rate Agreements might have faced the biggest losses under scenarios where trading manipulation resulted in a rise of five basis points in the BBSW.In a theoretical example given by ASIC, a customer who agreed to pay the BBSW rate on a notional amount of A$250 million might incur $30,000 in extra settlement payments at the end of a quarter.ASIC also drew scenarios where commercial borrowers may have been victims of BBSW manipulation.A borrower with a $2 million loan priced at the BBSW rate plus three per cent might incur additional