Quote from sheda:
Being exempt from a financial transaction tax in a market full of those who aren't, who reduce there investments or are put out of business altogether is no advantage for Goldman.
Although if a FTT was only imposed on retail traders, like the UK Stamp Duty Tax, it would not destroy liquidity in the same way that a universal FTT would. Of course it would not raise much revenue either and is morally indefensible on the part of the pro-FTT crowd. So they keep mum about this minor detail, and misleadingly sell it as "tax on bankers".
Goldman might well see a drop in customer volumes I suppose, but they would be able to continue with their high frequency business and they would likely see some competition disappear.
Agree that it is debatable whether Goldman and others would actually benefit overall, but they will defend their interests at the retail guys expense as a necessary "compromise" with the FTT crowd.
Just my three cents worth!