Is there an announcement before an ipo or SO does it have a specific time?

Initial public offerings (IPOs) and secondary offerings (SOs) have different characteristics regarding the announcement and timing:

1. IPO Announcement: An IPO is typically announced several weeks or months in advance, with the date and price range for the offering being disclosed. The company will file a registration statement with the SEC, which includes the prospectus, and the underwriter will gauge investor interest to set the final offering price.
2. SO Announcement: A secondary offering can be announced at any time, but it often follows a lock-up period, which restricts the sale of a company's shares by insiders. The announcement usually includes the number of shares to be sold and the selling shareholders.

In summary, IPOs have a more structured and publicized process with a set date and price range, while secondary offerings can be announced at various times and are often driven by the needs of the selling shareholders.