A relative-value options strategy that sells index volatility and buys single-stock volatility (or vice versa), monetizing the gap between an index's implied volatility and the volatilities of its constituents. The trade is structurally short index correlation: it profits when stocks move idiosyncratically rather than together.
How it works
Index variance equals the weighted sum of constituent variances plus a cross-correlation term, so index implied vol trades rich relative to component vol when implied correlation is high. A classic dispersion book sells index straddles/variance and buys constituent straddles/variance, leaving a position that is long dispersion and short realized correlation; it pays off when single names decouple.
Why it matters now
In 2025-26 the trade is "alive" because mega-cap concentration (Mag7) and divergent AI-capex winners-versus-losers depress realized index correlation, rewarding stock-picking over directional duration bets — hence "the dispersion trade is alive, the duration trade is not."
Example
If S&P 500 implied correlation is priced at 0.45 but realized correlation collapses to 0.25 as individual names report idiosyncratically through an earnings season, a short-correlation dispersion book — short index variance, long the constituent basket's variance — captures that ~20-point gap, with the long single-name leg outperforming the short index leg.
Frequently asked
- What is a dispersion trade?
- A dispersion trade is a relative-value options strategy that sells index volatility while buying single-stock volatility, monetizing the gap between an index's implied vol and its constituents' vols. The structure is short index correlation: it profits when component stocks move idiosyncratically rather than in lockstep. A typical book is short S&P 500 variance and long a basket of single-name variance.
- How does a dispersion trade make money?
- A dispersion trade makes money when realized correlation falls below the implied correlation priced into the index. Because index variance equals weighted constituent variance plus a cross-correlation term, the index leg trades rich when implied correlation is high. If stocks then report earnings idiosyncratically and decouple, the long single-name vol leg outperforms the short index vol leg, capturing the correlation gap.
- Why is the dispersion trade alive in 2025-26?
- The dispersion trade is alive in 2025-26 because mega-cap concentration and divergent AI-capex winners-versus-losers depress realized index correlation, rewarding stock-specific moves over directional index beta. With the Mag7 and AI narrative splitting names into clear winners and losers, single stocks decouple even as the index drifts—exactly the regime that rewards short-correlation books.
- How does a dispersion trade differ from a straight short-volatility trade?
- A dispersion trade is short correlation, not outright short volatility. A naive short-vol trade loses whenever realized vol rises, regardless of structure. A dispersion book sells index vol but offsets with long constituent vol, so it can stay roughly vega-neutral and profit specifically when stocks decouple—even in a high-volatility environment, provided that volatility is idiosyncratic rather than correlated.
- What is the main risk in a dispersion trade?
- The main risk in a dispersion trade is a correlation spike, where stocks move together in a broad sell-off. In events like February 2018's Volmageddon or the March 2020 COVID crash, realized correlation surged toward 1, the short index variance leg blew out, and the long single-name leg failed to compensate—producing sharp, convex losses for short-correlation books.