Small and Independent Business Protection Act of 1981

Small and Independent Business Protection Act of 1981 - Prohibits a person from merging or consolidating with, or acquiring a majority of the stock or assets of, any other person engaged in commerce if: (1) each person has assets or sales exceeding $500,000,000; or (2) one person has assets or sales exceeding $500,000,000 and the other person has 20 percent or more of the sales in any significant market during the year immediately preceding the acquisition.

Specifies affirmative defenses for such transactions.

Vests the authority to enforce compliance with this Act in the Attorney General of the United States and the Federal Trade Commission (FTC). Requires that procedures be adopted by which parties to such a transaction can ascertain if their transaction falls within the terms of one of the affirmative defenses, unless there is proof that such advice was based upon an intentional misstatement by the party requesting the advice.

Permits injunction relief for private parties in the same manner as prescribed in the Clayton Act.