Nevertheless, the upshot of the proposed bill for Blackstone's would be to wipe billions of dollars off the valuation of the buy-out giant.

ECONOMIST: More transatlantic gripes

The Baucus-Grassley legislation has come to be known as the "Blackstone Bill, " because it was introduced shortly after Blackstone announced its initial public offering earlier this year.

FORBES: Magazine Article

Another provision in the bill would change the tax treatment of publicly traded private-equity firms, such as Blackstone and Fortress Investment Group.

ECONOMIST: Private-equity firms battle to keep their tax perks