All-Holders Rule Law and Legal Definition
All holders rule is a Securities and Exchange Commission rule that prohibits a public offering by the issuer of shares to some, but not all, of the holders of a class of shares. The rule is codified at 17 CFR 240.14d-10 which speaks about equal treatment of security holders. According to 17 C.F.R. § 240.14d-10(a) a bidder's tender offer must be open to all security holders of the class of securities subject to the tender offer.
It can also refer to the SEC rule requiring a tender offeror to make its offer to all the target company's shareholders.