SESS (Primary Session)
Definition / Formula
The session carrying the largest share of traded volume, chosen from Tokyo, London and New York.
share(s) = volume in session s / total session volume
primary = top session, only if share(top) - share(second) >= 0.05
Sessions: Tokyo 09:00 to 17:00, London 08:00 to 16:30, New York 09:30 to 16:00, each in local time. Where two sessions overlap, the volume goes to the later-opening one. Volume outside all three is not counted.
Window: every bar in the stored 5-minute history: 21 weekdays on the weekday calendar or 20 weekend days on the weekend calendar, today’s partial day included.
Significance margin: 5 percentage points. Without that lead there is no primary and all three tags stay dim.
Minimum sample: 5 complete New York regular-hours sessions. Below that no primary is chosen and all three tags stay dim. A TradFi instrument closed for the weekend also shows three dim tags.
Related threshold: a session is listed as recommended at a share of 20 percent or more. That list is not shown in this column.
UI Breakdown
Three fixed tags in order: TKY, LDN, NY. The primary tag is drawn at full brightness, the other two are dim. Hovering the cell lists all three shares to one decimal.
| Control | Action | Effect |
|---|---|---|
| Column header | click | sort descending (largest first); click again to flip |
| Session badges in the header | click | multi-select, primary session |
Value Ranges
| See | Value Band | Status | Visual Appearance |
|---|---|---|---|
 | primary = tokyo | Tokyo carries the volume | TKY bright, others dim |
 | primary = london | London carries the volume | LDN bright, others dim |
 | primary = ny | New York carries the volume | NY bright, others dim |
 | No session payload | Not available | Empty cell |
Summary: SESS reports which trading session carries the largest share of the instrument volume.