RTH vs ETH

What is RTH vs ETH?

RTH vs ETH is the split between Regular Trading Hours, the official cash session (9:30am to 4:00pm ET for US equities, with index futures' RTH conventionally aligned to it), and Extended or Electronic Trading Hours: the overnight Globex session in futures, pre-market and after-hours in stocks. The older shorthand was pit hours versus Globex. Participation differs sharply between the two: RTH carries the bulk of institutional volume, while ETH is thinner, so overnight moves happen on less volume and can be easier to push and quicker to reverse.

The split matters because reference levels are convention-dependent. VWAPs, opening ranges, profiles, and high/low statistics all change depending on whether they are computed on RTH-only or full 24-hour data, and overnight/ETH levels such as the Globex high and low form their own reference set heading into the day session.

How traders use it

• Choosing and keeping a convention: building a volume profile or session VWAP on RTH-only data to match cash-session structure, or on full ETH data to capture the whole auction, and not mixing the two mid-analysis.
• Reading overnight inventory at the open: where ETH traded relative to the prior RTH close frames the opening gap and whether early trade is likely to correct an overnight extreme; a tendency, not a rule.
• Treating ETH extremes as references: overnight highs and lows are widely watched levels the day session frequently tests, which makes them natural planning spots rather than automatic trade triggers.