The New York Times has an article making the important and under-noticed point that a lot of money in the stock market is tax-exempt:
a dwindling number of investors are subject to the taxes on investment gains that are set to rise at the end of the year, with most stocks held in accounts that are exempt from taxes.
For example, only 14.7 percent of American households have mutual funds in taxable accounts, down from as high as 23.9 percent in 2001, according to data from the Investment Company Institute....
While data on the tax status of all stockholders is hard to come by, many economists agree than an increasing proportion of the entire equities market is now held by retirement investors whose holdings are not subject to current tax law; by foreign investors who don't pay American taxes, or by institutional investors like insurance companies and pension funds that are exempt from taxes.
The Times doesn't mention university and foundation endowment funds, but they count, too.
If this data is indeed hard to come by, Congress may want to rectify that, because it's data that is important in setting public policy. Advocates of the tax increases see it as a reason to go ahead with the increases because they won't affect that many people that much, anyway. But critics of the tax increases see it as a reason the tax increases won't raise that much money, and that those recommending additional revenues for the government should consider looking at those other piles of money that are now tax-exempt.