Triple Witching – paper review

This article presents a brief review and listing of academic papers on triple witching.

Summary

The expiry of stock index futures, stock index options and stock options happens in a programmed calendar throughout the year. On four days a year these three different types of derivative all expire on the same day – the third Friday of the months of March, June, September and December. This day is sometimes referred to as triple witching day, and is associated with increased trading volumes and volatility.

Review

Following the 1987 stock market crash there was great interest in program trading (a term not so commonly used today) and its impact on volatility. This led to a minor flurry of academic interest in associated topics such as triple witching.

The earliest mention of triple witching we can find in an academic paper is Feinstein and Goetzmann (1988), which looked at the increased volatility caused by the coincident expirations. A couple of years later Stoll and Whaley (1990) found greatly increased trading volume in the last half-hour on expiration days. However, they did not find any significant difference between stocks subject to program trading and other stocks.

In June 1987 the settlement of S&P 500 and NYSE index futures was changed (to settle at the open and not the close) in an attempt to decrease the impact of expiration. The effect of this was the topic of the most cited paper on triple witching, Stoll and Whaley (1991). Not surprisingly, perhaps, they found that volume and volatility of the S&P 500 and NYSE contracts was lower at the close and higher at the open for the period after June 1987 compared to the period before. The impact on price at the open was slightly smaller post-June 1987 than it had been at the close pre-June 1987.

Academic interest in triple witching then waned, albeit articles continued to appear on the more general topic of option expiration.

A rare, recent article (Stratmann and Welborn, 2012)  found a positive relationship between ETF settlement failures and ETF short sale volume, the cost to borrow ETFs, and triple witching days.

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