S&P 500 is a buy whenever the VIX is above this number: RBC

RBC Capital analysts suggested in a note Monday that the S&P 500 becomes a compelling buy when the VIX, a key measure of market volatility, surpasses 35.

The comments follow recent turbulence in global equity and futures markets, with a sell-off driven by various factors beyond just recession fears, according to the bank.

RBC Capital notes that the American Association of Individual Investors (AAII) survey has shown "net bullishness roughly one standard deviation above the long-term average," highlighting stretched positioning in US equity futures, particularly in S&P 500 and Nasdaq contracts.

Additionally, they say that the S&P 500 has historically struggled in the August-October timeframe over the past five years.

The bank notes that the VIX, sitting around 50 early Monday morning and peaking at 65, has surpassed levels seen during previous market stress periods such as the 2001-2002 tech bubble unwind, the 9/11 attacks, and the Iraq War.

RBC Capital's back-testing indicates that "the S&P 500 is a buy on a 12-month forward basis when the VIX is above 35."

RBC Capital also highlights that the tone from companies in the current reporting season does not align with fears of an impending recession. Despite recent poor seasonality and US election dynamics posing challenges, the economic backdrop and labor dynamics suggest stability.

As for market movements, RBC Capital is closely monitoring the S&P 500's response to potential declines, noting that typical pullbacks range from 5-10%. They expect to see significant price action around the 5,100 mark, which would represent a 10% drop from recent highs.

Overall, RBC believes that while emergency rate cuts by the Fed might not immediately calm markets, the VIX crossing the 35 threshold historically signals a strong buying opportunity for the S&P 500 on a forward-looking basis.