Wall Street Journal, Democrats Weigh Tax On Financial Transactions, by John D. McKinnon:

Taxing financial transactions on Wall Street is gathering support in high places.

With federal budget deficits soaring, policy makers and other advocates are eyeing the huge sums that could be raised as a way to cover the costs of new initiatives.

This week, the left-leaning Economic Policy Institute floated the idea of a national transaction tax that would raise $100 billion to $150 billion a year. The tax, at a rate of 0.1% to 0.25% of the value of the trade, would be levied on all financial transactions such as stock trades, but not on consumer transactions such as with credit cards. …

Many economists have argued against a financial-transactions tax on policy grounds, saying it could have consequences for markets, in part by driving activity outside the U.S. Critics said it also would throw sand in the gears of capital markets.

Still, some appear to be changing their minds. "I'm not as hostile as I used to be," said Len Burman, a Syracuse University professor and former head of the Tax Policy Center, a venture of the left-of-center Brookings Institution and Urban Institute. Curbing frequent trading might be a good idea, he said, though he is "skeptical this is the best way to do it."