Under American securities law, there are two-time windows commonly referred to as "quiet periods" during an IPO's history. The first and the one linked above is the period of time following the filing of the company's S-1 but before SEC staff declare the registration statement effective. During this time, issuers, company insiders, analysts, and other parties are legally restricted in their ability to discuss or promote the upcoming IPO (U.S. Securities and Exchange Commission, 2005).

The other "quiet period" refers to a period of 10 calendar days following an IPO's first day of public trading. During this time, insiders and any underwriters involved in the IPO are restricted from issuing any earnings forecasts or research reports for the company. When the quiet period is over, generally the underwriters will initiate research coverage on the firm. A three-day waiting period exists for any member that has acted as a manager or co-manager in a secondary offering.
Summarize what and when the quiet periods occur during an IPO.
There are two quiet periods during an IPO during which company insiders cannot promote the IPO or issue information that might affect it. One is after the Form S-1 is filed but before the SEC approves it, and one is the 10 calendar days after an IPO's first day of trading.