The White House press office determines full lid timing based on President Trump’s daily public schedule, including any travel movements, remarks, bilateral meetings, or pool events listed in official calendars. Early September 2026 typically features the post-Labor Day return of congressional sessions, potential executive actions, and routine domestic or diplomatic commitments that can extend coverage into the evening or prompt later lids. Markets resolve using the first full lid time from sources such as Roll Call’s Factbase or Forth pool reports, with only explicit full lids counting toward an early close by 6:30 PM ET. Late announcements, unscheduled statements, or extended travel often shift outcomes, while lighter days with executive time frequently produce earlier wraps.