Wall Street Tax Act of 2021 This bill imposes a 0.1% excise tax on certain purchases of stocks, bonds, and derivatives. The tax applies to the purchase of a security if (1) such purchase occurs on, or is subject to the rules of, a qualified board or exchange located in the United States; or (2) the purchaser or seller is a U.S. person. The tax applies to transactions with respect to a derivative if (1) the derivative is traded on, or is subject to the rules of, a qualified board or exchange located in the United States; or (2) any party with rights under the derivative is a U.S. person. The bill exempts from such tax (1) initial issues of securities; and (2) any note, bond, debenture, or other evidence of indebtedness which is traded on or is subject to the rules of, a qualified board or exchange located in the United States, and has a fixed maturity of not more than 100 days. The tax applies to transactions by a controlled foreign corporation and must be paid by its U.S. shareholders.