Between the turmoil in China, oil price swings and more uncertainty from the Fed - volatility in the markets is soaring.
And to cap off the week - an occurrence that happens but four times a year - today is known as quadruple witching day.
Known to traders simply as "quad witch", it falls on the third Friday of the last month of every quarter. It refers to the simultaneous quarterly expiration of four sets of options: individual stock options, stock futures, stock indexes and stock index futures.
With so many market forces at work at the same time, quadruple witching days have built up a reputation for greater volumes and volatility.
But history suggests the "quad witch" isn't as ominous as it sounds.
Data from analytics platform Kensho shows that since 2002 (when single-stock futures were added to the mix, turning "triple witch" into "quadruple witch"), markets have typically moved higher on the day. The S&P500, Dow Industrials and have all traded higher the majority of the time and returned 0.2 percent on average across the 54 occurrences. On four of the last five quad witching days, the Dow has finished the session with gains.
All S&P sectors have also been typically positive on the day and volatility, as measured by the VIX index, has traded lower nearly 65 percent of the time and lost 1.8 percent on average.
Crunching the numbers, we also found that not all quad witching days are the same. History shows that market forces have been most volatile on quad witch in March. The S&P500 trades positive half the time and negative half the time. Meanwhile, September and December tend to be more bullish from a season perspective. Stocks have historically moved higher nearly 70 percent of the time on the date and see average returns of 0.5 percent in September and 0.3 percent in December.
The day itself may not be particularly ominous for markets, but watch out for the week following the quad witch. This is a period when volatility tends to rise and stocks fall. In the 5 days following the occurrence since 2002, the Dow Industrials and S&P500 have both traded negative about 70% of the time and lost 0.6% on average. All 10 S&P500 sectors typically trade lower and volatility rises.
So as we cap off a jam-packed week, the quad witch may be one less thing to fear.