How are bid, ask, and last size quotes displayed for stocks?

Unless specifically modified, the default trigger method for all stocks is the "Last" method as described within the User's Guide. For US options the default trigger method is the "Double bid/ask" method, where two consecutive ask price (bid price) values must be less than (greater than) or equal to the trigger price, and the second bid or ask must have greater size if it is at the same price level as the first bid or ask.  For Forex cash pairs (for example EUR/USD currency pair), the default trigger method is single "bid/ask", where the ask price (bid price) value must be less than (greater than) or equal to the trigger price. For all other contracts like Futures and Futures Options contracts the default trigger method is the "Last" method as described within the User's Guide. Find information on the…

To comply with SEC regulations, US stock quotes, including bid, ask, and last size quotes, are now shown in shares (not in lots) in all of our trading platforms.

Find out more at https://www.sec.gov/rules/final/2020/34-90610.pdf…

Available Size in Order Presets, Hotkeys and Buttons means the current Bid Size or Ask Size.

Additional Information…

There is no direct configuration option for "Last Size Extra Decimal" within Client Portal at this time. However, Client Portal does read and apply the setting you have configured in Trader Workstation, IBKR Desktop, or IBKR Mobile. Your Last Size values in Client Portal will be formatted according to the decimal setting you have established on another platform…