The Fed’s still-hawkish bulls are about to lose a significant force helping to keep US stocks in check amid this week’s macroeconomic events.

An estimated $4 trillion in options are due to expire on Friday, a monthly event that tends to add to the volatility of the trading day. This time, the S&P 500 has stagnated within 100 points, around 4,000 for weeks, with heavy volume providing a positioning reset that could drive market moves. Given the brutal backdrop that has emerged in recent days, from a series of interest rate hikes by central banks around the world to signs that the US economy is starting to slide, fears are growing that the expiry will be a no-brainer.

Spot Gamma founder Brent Kochuba said options tied to the S&P 500 4,000 accounted for the most considerable portion of expiring open interest in the weeks through Friday. The price of the index acts as a constraint.

Stocks were already under pressure on Thursday as the European Central Bank joined the Fed in raising rates and warning of more pain. The S&P 500 fell 2.5%, closing below 3,900 for the first time in five weeks.

Goldman Sachs Group Inc strategist Rocky Fishman said holders of options tied to its $4 trillion index and individual stocks would have to roll over existing positions or initiate new ones at critical dates.

This time, the event coincided with the quarterly expiration of stock index futures, an ominous phenomenon known as triple witchcraft. Added to this is the rebalancing of benchmark indices, including the S&P 500. This combination tends to spark one-day volumes that rank among the highest of the year.

With this week’s consumer price report and the Federal Open Market Committee’s final meeting of the year, options traders are bracing for turmoil. In a sign of heightened anxiety, derivatives markets showed exceptional performance on Monday, with the Cboe Volatility Index, a volatility index that measures option costs, up more than 2 points, while the S&P 500 gained 1.4%. It was the most significant unanimous gain since 1997.

That dynamic played out on Wednesday when the S&P 500’s decline coincided with a slide in the VIX, reversing the historical pattern of them moving in opposite directions.

Danny Kirsch, director of options at Piper Sandler & Co, said the unwinding of hedges removed market support and opened the door for more volatility.