// CHAPTER 5 · 5:58
From December 6, one hour a night belongs to the ATSs alone.
Walkthrough
Chapter 5: Twenty four hour trading
Video coming shortly
The overnight session is one piece of a larger change, and the twenty four hour theater tracks the whole of it.
From December 6, no Form 1 exchange trades between eight and nine at night. The exchanges take a sunset hour and start at nine. The alternative trading systems that run through it do not stop. For that hour the only US equity liquidity sits on an ATS, with no consolidated quote behind it.
That has consequences nobody had to think about before. Which trade date does an 8:30pm fill belong to. Whether a day order survives a session boundary. Whether a protocol session can run a week without resetting its sequence numbers.
The FIX Trading Community published seventeen questions on exactly that, and gave us written permission to reproduce the whole document. So it reads in a browser instead of a PDF, searchable, every protocol tag linked to its specification. Author and copyright FIX Protocol Limited. They wrote it. We host it. Beside it sits our own question bank, which answers the same ground in plain language.
