Is it possible to buy a company's stock from 8 am to 9:30 am on the day of the company's IPO using an online brokerage that is? Or does the IPO stock only become available when the market opens at 9:30?
The first moment of trading usually occurs even later than that. It may take a few hours to balance the current buy/sell orders and open the stock. Watch CNBC when a hot IPO is about to open and you'll see the process in real time. If you miss it, look at a one day Yahoo chart to see when the open occurred.