26 U.S.C. § 317

For purposes of this part, the term "property" means money, securities, and any other property; except that such term does not include stock in the corporation making the distribution (or rights to acquire such stock).

For purposes of this part, stock shall be treated as redeemed by a corporation if the corporation acquires its stock from a shareholder in exchange for property, whether or not the stock so acquired is cancelled, retired, or held as treasury stock.