SPX Regular Trading Hours (RTH) Gap

If you trade indices, I highly recommend using the SPX RTH Gap and watching how price reacts from the 25%, 50%, and OTE zones every single day. I track the levels on SPX and trade the reactions on ES — it has been a great addition to my trading.

The RTH (Regular Trading Hours) gap is the area between yesterday's 4:00 PM close and today's 9:30 AM open. When SPX opens higher or lower than it closed, it leaves a gap on the chart — and that gap becomes a map of levels for the session.

Two reference points define the gap. Everything else — the 25%, 50%, 62% and 70.5% retracement levels — is measured inside this range.

The gap represents unbalanced price delivery. It doesn't need to fill immediately — price may only partially fill it while balancing everything that happened overnight.

Once the open prints, drop a fib from one boundary of the gap to the other. The 0.25, 0.5, 0.62 and 0.705 levels become the reference zones for the entire morning session.

1. Shallow retracement (25–50%)

   SPX opens near liquidity but fails to take it in the first 15 minutes.

2. OTE retracement (62–70.5%)

   SPX takes the nearest liquidity level in the first 15 minutes, then retraces deep.

3. Break of 70.5%  full fill

   Price drives straight through the OTE — continuation toward a complete gap fill.

4. Overlap Gap

   SPX opens inside an old unfilled RTH gap, creating a new RTH gap within the old one.

A shallow retracement — typically into the 25%–50% zone — occurs when the market doesn't require a deeper correction. This often happens when SPX opens near a liquidity level but fails to take it during the first 15 minutes after the open.

Both examples below: price fails to take the buy-side liquidity at the open, retraces into the 25% zone, prints a 2-minute CISD, then continues to the liquidity target (BSL).

A retracement into the OTE of the RTH gap — between 62% and 70.5% — often occurs when SPX takes the nearest liquidity level during the first 15 minutes after the open.

This scenario can offer two separate trades:

1. A reaction from the liquidity level toward the OTE of the RTH gap.

2. A reversal from the OTE toward the important higher-timeframe level.

Sometimes SPX moves away from the gap without even reaching the 25% level. In other cases, price takes the nearest liquidity level but lacks the volume or time to reach the OTE before the session ends.

Keep them marked on your chart. These gaps can act as strong magnets for price — future targets, reversal areas, or important reaction zones when SPX returns to them.

The final scenario occurs when SPX opens and immediately moves into the OTE of the RTH gap. If price breaks through the 70.5% level, this can offer a continuation trade targeting the complete fill of the gap and the opposite liquidity level.

As we learned, when SPX breaks above or below the 70.5% level of an RTH gap, price will often continue to fill the gap and then reach for nearby buy-side liquidity (BSL) or sell-side liquidity (SSL).

But what happens after the gap is filled?

If the gap has been filled while the main higher-timeframe objective remains open, we want to look for a reversal after price takes BSL or SSL.

The first trade should be based on a 2-minute market structure shift or CISD. The initial target is the 25% level of the RTH gap, because this level can act as a barrier and produce a reaction.

For example, if the main objective remains higher, price may first take SSL and then retrace back toward the gap. The 25% level becomes the first target.

From there, one of two scenarios is likely to unfold: price may remain within the gap for the rest of the trading session, or it may break and hold beyond the 25% level. Once the 25% level is successfully broken, price is more likely to continue toward the remaining higher-timeframe objective.

Sometimes SPX opens inside an old unfilled RTH gap, creating a new gap within the old one. The area where the two gaps overlap becomes a key zone — that's where we want to see price retrace and get rejected.

We're not going to use the entire overlap area. We only use the overlap between the unfilled portion of the previous gap and the current gap — that's the true overlap zone that matters.

Why? When trading an RTH gap, the goal is to see whether price has balanced everything that happened overnight. Sometimes that balancing is only partial — SPX may reverse from the gap's OTE, leaving part of the gap unfilled. That remaining unfilled portion becomes an area we expect price to revisit in the future — not the same day, but eventually.

Once the overlap zone has been identified, we apply OTE to that overlap area.

This confirms the market is responding to the overlap zone before we commit to a trade

Remember — price does not seek to fill gaps. Price seeks to balance everything that happened during the overnight session.

Of course, SPX may sometimes fill the gap immediately, ignoring both the nearby liquidity level and the OTE. Nothing works 100% of the time. That is exactly why we wait for confirmation from a 2-minute shift in structure or a 2-minute CISD before entering the trade.

We never blindly anticipate a reaction simply because price has reached a Fibonacci level. The level gives us an area of interest — price action must confirm the entry.