The S&P 500's roughly 6% rally over the past five days may be more mechanical than fundamental, driven largely by options-market positioning, according to an analysis by Mott Capital Management's Michael Kramer published in MarketWatch. Falling implied volatility and heavy bullish call buying pushed the index higher, but dealer positioning has now turned in a way that could cap further gains near 7,800.
The S&P 500 has risen about 6% over the past five days, but the advance may be more mechanical, driven by options positioning and dealer hedging rather than by an improvement in investors' fundamental outlook, according to an analysis by Mott Capital Management's Michael Kramer, published by MarketWatch. The rally began after the July 29 Federal Reserve meeting, when a rapid shift in dealer gamma positioning, falling implied volatility and heavy activity in bullish call options appears to have amplified the move.
Gamma positioning fueled the rebound
Heading into the Fed's July 29 decision and a heavy round of earnings, options positioning had left dealers with significant negative-gamma exposure, the analysis found. In a negative-gamma environment, dealers typically hedge in the same direction as the market, buying as prices rise, which can amplify moves in either direction. The S&P 500's advance was likely reinforced by this negative-gamma positioning.
The market has since shifted to a positive-gamma regime, in which market-maker hedging flows tend to move against the market's direction. As a result, further gains could be capped as market makers become sellers, removing the tailwind that initially pushed the index higher.
Falling volatility and call buying added fuel
The Cboe Volatility Index, or VIX, fell to around 16 from about 21 previously after the Fed meeting and a heavy round of earnings. As implied volatility declined, put premiums lost value, prompting investors to unwind those positions — action that may have forced dealers to adjust hedges in a way that mechanically pushed the market higher.
A surge in S&P 500 net call volume over the past few trading sessions likely added further fuel to the rally, the analysis said. If dealers were taking the other side of that call buying, their hedging activity may have reinforced the index's advance, creating a feedback loop in which rising prices generated more demand for calls.
Resistance builds near 7,800
Call positioning around the 7,800 strike price appears particularly heavy, based on options data from LSEG cited in the analysis. The put wall sits at 7,400, the level with the greatest concentration of put gamma, just above where the rally began.
A failure to clear 7,800 could leave the index vulnerable to consolidation or a pullback, though positive dealer gamma could help cushion any decline. But if the S&P 500 falls below the positive-gamma threshold and dealers return to negative gamma, selling could accelerate and erase a larger part of the rally, the analysis warned.
The index also moved from oversold, trading below its lower Bollinger Band, to overbought, above its upper band, in a matter of days. That does not necessarily signal an imminent selloff, but it suggests the options-driven forces that accelerated the rebound are fading.
Source: MarketWatch
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