Interactive Brokers is trading 6.78% down now at $84.54 in after-hours trading after closing at $90.69 on September 18, 2026, with no clear company-specific negative catalyst identified.
- Interactive Brokers announced expanded AI-tool connectivity on September 18.
- Earlier announcements covered X Cashtags and Japanese trading programs, but neither directly explains the drop.
- The broader market was mostly positive, making index-wide weakness an unlikely explanation.