A corporate action announcement is the statement in which an issuer makes public an event that will affect holders of its shares or bonds, such as a dividend, a rights issue, a split, a merger or a redemption. It is released through the channels required by listing rules, and it sets out the type of event, the securities affected, the terms or rate, and the key dates: record date, ex-date, payment date and any deadline for choosing between options.
The announcement is the source from which data vendors, depositories and custodians build their own records, a step called corporate action event capture. Information may arrive in stages and be revised, so each version is tracked. Custodians pass the details to account holders in a corporate action notification. It applies to a mandatory corporate action and a voluntary corporate action alike, and its timing is recorded as the corporate action announcement date.