The day a clearinghouse can make a notice of intent to deliver stocks (commodities, indexes, etc.) to a buyer in fulfillment of (futures) contracts is defined as the notice day.
Additionally, we may mention that most initial public offerings (IPO) agreements include lockup provisions. these lockup provisions prohibit insiders from selling their shares for an agreed period (from 90 days to several years, usually 180 days) after the IPO.
The requirements for the sale of the pre-IPO shares are defined by SEC Rules 144, 144(k), and 701. Numerous empirical studies examine the impact of lockup expiration on the stock price behaviour.