This will certainly do [something]. What? I think is uncertain. Unintended consequences can be a bitch and without cooperation with other major market this could merely be vast offshoring of European trades.
"Under the proposal, a trade of shares worth 10,000 euros would face a tax of one-tenth of 1 percent, or 10 euros. A trade of a derivative would face a tax of one-hundredth of 1 percent. But that tax would be applied to the notional value, which can be very large relative to the cost of the derivative. So a credit-default swap on 1 million euros of debt would have a tax of 100 euros, or about 0.4 percent of the annual premium on such a swap.
The tax would be owed no matter where the trade took place, as long as a European security or European institution was involved. The law has been written so broadly that if a French bank bought shares in an American company on the New York Stock Exchange, the tax would be owed.
To get out of the tax, a financial institution would have to do more than simply move its headquarters out of the 11 countries that now plan to impose the tax. It would also have to forgo serving clients in any of those countries and trading in securities or derivatives from any of the countries. Officials are confident that no major institution will be willing to forsake such large markets as France, Germany, Italy and Spain. "