Interactive Brokers Updates TWS with Fractional Last Size Feature

Interactive Brokers has released build 10.44 (beta) of its Trader Workstation (TWS) platform, introducing updates to how trade size data is displayed for certain instruments.

Under the new build, TWS now displays fractional last size values for US stocks and warrants. The change allows traders to view trade sizes with decimal precision instead of rounded whole numbers, reflecting the growing use of fractional trading in US equity markets.

To activate the feature, users must navigate to Global Configuration within the TWS platform. From there, they need to scroll to the Display Settings section and locate the “Last Size Extra Decimal” setting. Traders can then enter the maximum number of decimal places they wish to display for stock last sizes.

Interactive Brokers Updates TWS with Fractional Last Size Feature

After configuring the preferred number of decimals, users must click “Apply” and then “OK” to save the changes. Once confirmed, fractional last sizes will become visible in the Watchlist and Portfolio panels, depending on the fields selected by the user.

The update is here to align the platform’s data display with trading activity that involves fractional shares, which has become more common among retail and professional participants. By allowing decimal precision in last trade sizes, the platform reflects execution data more accurately for instruments where fractional trading is available.

In addition, the company noted that if a user has configured a Size Divisor under the Advanced settings, this mode will remain active when the user opens Presets. This ensures that previously defined size display preferences continue to function alongside the new fractional last size setting.

Build 10.44 (beta) is currently available for users testing the latest version of TWS, with the update focusing on display customization rather than structural changes to order handling or execution functionality.

Company Overview

Interactive Brokers caters to diverse requirements, offering competitive fees alongside a wide array of trading options such as stocks, ETFs, options, futures, and other global assets. It distinguishes itself as a top-tier brokerage, particularly appealing to traders and investors seeking a straightforward trading experience. With Interactive Brokers’ user-friendly platform, users can execute trades seamlessly, benefiting from competitive spreads that enhance cost-effectiveness. 

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