Bloomberg Businessweek reported the world’s largest banks have presented a list of changes to a proposed U.S. ban on proprietary trading, seeking to escalate the lobbying effort against the Volcker rule five months before it takes effect.

According to the report, letters filed by bankers and their trade associations said the rule would increase risk, raise costs for investors, hurt U.S. competitiveness and be vulnerable to legal challenge.

“Regardless of how the final rule turns out, it will be a shock to the U.S. financial system, as banking entities will need to take extraordinary measures to attempt to implement it,” Barry Zubrow, executive vice president of JPMorgan Chase & Co. said in a 67-page letter. Goldman Sachs Group Inc., Morgan Stanley and Bank of America Corp. were set to submit their letters to regulators by today according to the Bloomberg report.
 
The Volcker rule was included in the 2010 Dodd-Frank Act in an effort to restrict risky trading at banks that operate with federal guarantees and is set to take effect in July even if the rule-making is still in progress, and would include a two-year transition period. The Federal Reserve would then have the ability to issue multiple one-year implementation extensions on a case-by-case basis.