17 CFR § 240.14e-1 - Unlawful tender offer practices.
As a means reasonably designed to prevent fraudulent, deceptive or manipulative acts or practices within the meaning of section 14(e) of the Act, no person who makes a tender offer shall:
(a) Hold such tender offer open for less than twenty business days from the date such tender offer is first published or sent to security holders; provided, however, that if the tender offer involves a roll-up transaction as defined in Item 901(c) of Regulation S-K (17 CFR 229.901(c)) and the securities being offered are registered (or authorized to be registered) on Form S–4 (17 CFR 229.25) or Form F–4 (17 CFR 229.34), the offer shall not be open for less than sixty calendar days from the date the tender offer is first published or sent to security holders;
(b) Increase or decrease the percentage of the class of securities being sought or the consideration offered or the dealer's soliciting fee to be given in a tender offer unless such tender offer remains open for at least ten business days from the date that notice of such increase or decrease is first published or sent or given to security holders.
(c) Fail to pay the consideration offered or return the securities deposited by or on behalf of security holders promptly after the termination or withdrawal of a tender offer. This paragraph does not prohibit a bidder electing to offer a subsequent offering period under § 240.14d–11 from paying for securities during the subsequent offering period in accordance with that section.
(d) Extend the length of a tender offer without issuing a notice of such extension by press release or other public announcement, which notice shall include disclosure of the approximate number of securities deposited to date and shall be issued no later than the earlier of: (i) 9:00 a.m. Eastern time, on the next business day after the scheduled expiration date of the offer or (ii), if the class of securities which is the subject of the tender offer is registered on one or more national securities exchanges, the first opening of any one of such exchanges on the next business day after the scheduled expiration date of the offer.
(e) The periods of time required by paragraphs (a) and (b) of this section shall be tolled for any period during which the bidder has failed to file in electronic format, absent a hardship exemption (§§ 232.201 and 232.202 of this chapter), the Schedule TO Tender Offer Statement (§ 240.14d–100), any tender offer material required to be filed by Item 12 of that Schedule pursuant to paragraph (a) of Item 1016 of Regulation M–A (§ 229.1016(a) of this chapter), and any amendments thereto. If such documents were filed in paper pursuant to a hardship exemption (see § 232.201 and § 232.202(d)), the minimum offering periods shall be tolled for any period during which a required confirming electronic copy of such Schedule and tender offer material is delinquent.