On an IPO’s first trade date, IBKR only allows using a Limit Order (you may select “Yes” to allow trading Outside RTH). You may use a Limit-on-Open order before the first actual trade. After the IPO’s first trade, once the stock is trading in the Secondary market, any order type can be used. Orders created and entered prior to the IPO’s first trade will be Price Capped by IBKR.
Please note that the Price Capping of orders will not be turned off for any specific symbol or account. Exchanges and regulators require Interactive Brokers and other brokers to impose various pre-trade filters and other checks to make sure that orders are not disruptive to the market and do not violate exchange rules. Before the IPO stock is actively trading, the Price Cap may be set relative to a published price for the anticipated IPO. On the morning of the first trade date, the indicative Bid/Ask may change during the primary exchanges IPO Pre-Launch Period. When that happens, the IBKR Risk Group can manually review the current indicative Bid/Ask and may or may not reset the Price Cap before trading begins. After trading begins, the Price Cap will update as designed from the real time bid/ask/last prices.