Correlation Swap
A Correlation Swap is an over-the-counter derivatives contract in which two counterparties exchange a fixed correlation strike against the subsequent realized pairwise correlation between a specified basket of assets, allowing direct trading of correlation as an asset class.
Correlation swaps emerged from the dispersion trading community as a cleaner instrument for expressing views on correlation without the operational complexity of managing a basket of options positions. Rather than assembling a dispersion trade from dozens of individual variance swaps, a correlation swap provides a single instrument whose payoff is directly linked to realized correlation.
The structure is conceptually simple: at inception, a strike correlation level is agreed upon (say, 0.45). At maturity, the realized pairwise correlation between all pairs of assets in the basket is calculated. If realized correlation exceeds the strike (say, 0.55), the buyer of correlation receives the difference multiplied by the notional amount. If realized correlation is below the strike, the seller profits. The payoff is therefore: (Realized Correlation - Strike Correlation) x Notional.
Pairwise correlation is calculated as the average of all correlation coefficients between every pair of stocks in the basket. For an index of fifty stocks, this means calculating 1,225 individual pair correlations and averaging them. The result captures how much stocks are moving together versus independently.
The primary users of correlation swaps are volatility hedge funds, bank derivatives desks, and insurers with exposure to correlation-sensitive products such as worst-of and best-of options. Banks that have sold correlation-sensitive structured products to clients often buy correlation swaps to hedge the resulting exposure in their books.
Pricing correlation swaps is complex because correlation itself is not directly observable in real time and is notoriously difficult to model. The implied correlation derived from comparing index variance to constituent variance (as in dispersion trading) serves as the primary benchmark for fair value, but model risk is significant.
Liquidity in correlation swaps is limited to sophisticated institutional counterparties. Bid-ask spreads are wide and documentation under ISDA Master Agreements is required. Retail investors have no practical access to correlation swaps, but the concept is important for understanding how professional traders think about systemic risk, portfolio construction, and the pricing of complex structured products.