The CBOE volatility index, which uses the prices of options on the S&P 500 to measure expected moves over the next 30 days, bounced off the 23-year low it hit on Friday, but is still at moderate levels. On the other hand, the CBOE Nasdaq 100 volatility index, which looks at the large-tech-centric index the same way that the VIX looks at the S&P, touched the highest level since November on Monday.
The Nasdaq 100 VIX does tend to remain higher than the S&P 500 VIX. But on Friday, the fact that the former closed above 18 while the latter closed below 11 means that the percentage gap between the two was the widest it has been since 2003, according to a CNBC analysis of FactSet closing-price data.
Unsurprisingly, this is a mirror image of what has been seen in the markets. The Nasdaq 100 tumbled 2.44 percent on Friday, while the S&P 500 slid just 0.08 percent. On Monday, the Nasdaq dropped 0.59 percent, while the S&P 500 slipped 0.1 percent.
To Chantico Global CEO Gina Sanchez, the higher level of expected volatility in the Nasdaq 100 is reasonable, given that the index is being driven by "one factor, which is expected growth," while the stocks within the S&P 500 "are being driven by highly idiosyncratic factors." The more limited number of drivers among Nasdaq 100 stocks translates into the potential for bigger mono-directional moves.
In addition, the Nasdaq 100 is a highly concentrated index. Just five stocks — Apple, Microsoft, Amazon, Facebook and Alphabet — account for more than 40 percent of the index, and are responsible for about half of its 17 percent rally this year.
Yet for Jim Strugger, derivatives strategist at MKM Partners, the S&P 500 could itself see more volatility soon.
"This could intensify a little bit as opposed to the complacency we see out of a lot of our clients of late," Strugger said Monday on CNBC's "Trading Nation."