Options pinning, the tendency of underlying prices to gravitate toward strikes with concentrated open interest near expiration, is well documented. However, given the rapidly changing options landscape, it is worth reassessing whether this effect still holds.
Reference [1] examines options pinning using data from 2016 to 2025, a period marked by the proliferation of weekly and zero-days-to-expiration (0DTE) options, based on 1.6 million near-expiry SPY contracts. The author pointed out,
We find no evidence of options pinning in S&P 500 expiration dynamics across five tests on 2,294 trading days (2016–2025). The significant finding (p < 0.001) shows the opposite: high near-expiry ATM open interest is associated with wider, not narrower, daily ranges. This is consistent with the gamma amplification mechanism documented by Barbon & Buraschi (2021) and the theoretical predictions of Jeannin et al. (2008) under net short dealer gamma.
We interpret these results as evidence of a possible regime shift in S&P 500 expiration dynamics—from pinning in earlier periods (as documented by Golez & Jackwerth through 2009) to amplification in the modern era, potentially driven by the structural growth of short-dated options and changes in dealer positioning. We offer this interpretation as a hypothesis for further investigation, not as a definitive conclusion.
In short, the paper finds no evidence of pinning. Instead, on days with high open interest, prices exhibit approximately 16% wider ranges, indicating a shift from pinning to amplification. This change is likely driven by the growth of short-dated options and increased retail demand for long options, which leaves dealers short gamma and leads to larger price moves.
An interesting point discussed in the paper is that open interest is more informative than implied volatility, signifying that dealer positioning is important information.
Let us know what you think in the comments below or in the discussion forum.
References
[1] Elms, N. (2026), From Pinning to Amplification: Evidence of a Regime Shift in S&P 500 Options Expiration Dynamics, 2016–2025, SSRN 6564078
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