(a) In general. Section 5881 of the Code imposes a tax equal to 50 percent of the gain or other income realized by any person on the receipt of greenmail, whether or not the gain or other income is recognized.

(b) Transactions occurring on or after March 31, 1988. For transactions occurring on or after March 31, 1988, greenmail is defined as any consideration transferred by a corporation (or any person acting in concert with the corporation) to directly or indirectly acquire stock of the corporation from any shareholder if:

(1) The transferring shareholder has held the stock (as determined under section 1223) for less than two years before entering into the agreement to transfer the stock,

(2) The shareholder, any person acting in concert with the shareholder, or any person related to the shareholder or to a person acting in concert with the shareholder made or threatened to make a public tender offer for stock of the corporation at some time during the two-year period ending on the date of the acquisition of the stock by the corporation, and

(3) The acquisition is pursuant to an offer that was not made on the same terms to all shareholders.

(c) Transactions occurring before March 31, 1988. For transactions occurring before March 31, 1988, greenmail has the same meaning as in paragraph (b) of this section, except that it does not include any consideration transferred by any person acting in concert with the corporation described in that paragraph.

(d) Effective date. Generally, section 5881 of the Code applies to consideration received after December 22, 1987, in taxable years ending after that date. However, section 5881 does not apply to any acquisition of stock pursuant to a written binding contract in effect on December 15, 1987, and at all times thereafter before the acquisition.