Corporate actions by a company refer to initiating a process that is set to impact the stock of that company. Corporate actions include declaring dividends, mergers and acquisitions, issue of bonus shares, etc.
When there’s a corporate action announced, the same is adjusted for in your smallcase on the ex-date.
For example, when there’s an issue of bonus shares, these additional shares will be reflected in your demat account once you receive them. However, on smallcase, we adjust for the same on the ex-date itself