The number of symbols that can be viewed simultaneously via the TWS deep book windows (including BookTrader, Market Depth and ISW) is determined as follows: one unique symbol for every 100 allowed lines of market data, with a minimum of three and a maximum of 60.
For example, a client with the default allowance of 100 lines of data will be able to simultaneously view deep data for three different symbols. Please note that multiple deep book windows for the same symbol can be opened without impacting market data limits. Continuing this example, this client could open the symbol IBKR in BookTrader, Market Depth and ISW and still be able to view deep data for two more symbols. A client who, based on commissions, equity or other criteria, is allowed 500 tickers will be able to simultaneously view deep data for five unique symbols. Please note that this number may change month to month if the number of allowed tickers for your account changes.
Additionally, you can increase your allowance of simultaneous quotes windows by purchasing monthly Quote Booster packs at USD 30.00 per pack. See: How do I subscribe to a Quote Booster Pack?
To find out more about Market Data Allocation and Quote Booster packs, see the Market Data Display section of the Market Data page on our website.