Before the Bell
An American exchange is open for six and a half hours and shut for seventeen and a half. A perpetual futures venue quotes the same stocks throughout. Between seventy and ninety per cent of a typical opening gap is already visible on that venue five minutes before the bell, with no model of any kind. What the number is made of decides what it is worth: the venue's reference feed explains as much as its traded price, which makes it a data source rather than a view.