Articles on: Trading Questions

SPX and VIX spot prices

You may be wondering why the spot prices for VIX and SPX within the order flow is different from what you may see on the stock chart.

This is because SPX and VIX are traded on a futures basis. More information here:

SPX: https://www.marketwatch.com/investing/future/es00

Mini VIX Futures: https://www.cboe.com/tradable_products/vix/vix_futures/

Why do we do it that way?

We track SPX options flow against ES futures because futures are often where institutional S&P risk is expressed and hedged first. SPX options themselves are listed on the S&P 500 cash index, but ES provides the most liquid real-time benchmark for interpreting that flow.

Other considerations

SPX and SPXW option flow will most often appear as “splits” rather than “sweeps.”

This is due to how SPX options are structured. Unlike equity options (e.g., AAPL), which are fragmented across 15+ exchanges, SPX options are primarily traded on a single venue (Cboe). Because of this, there are no multiple exchanges to route across, and true sweep orders (ISO-style multi-exchange executions) generally do not occur in the SPX market.

Instead, large institutional orders are typically executed in pieces within a single order book, resulting in multiple prints over a short period of time — what we classify as splits.

Key takeaway: In SPX and SPXW, “splits” are not weaker signals — they are often how institutional-sized orders are executed.

Updated on: 04/09/2026

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