When derivatives are based on a stock, a corporate action changes the value of the underlying stock or the terms of delivery, so the terms of the contract, such as the strike price and the quantity, may be adjusted. Whether to adjust and how are decided by the exchange or the clearing house for listed options. For over-the-counter trades, FIX, a trade data protocol, has a field that specifies the method of adjustment for each trade.
Corporate action
- Japanese
- コーポレートアクション
- Last reviewed
- October 23, 2026
A corporate action is an event carried out by the issuer of a stock, such as a stock split, reverse split, merger, company split, or dividend, that affects the value or trading terms of that stock.