Does a sharp one-day rise in VIX's RSI predict a bigger spike ahead?

A fast jump in VIX's RSI looks like a momentum trigger. The oscillator lurches higher, volatility is clearly accelerating, and the instinct is to read it as a breakout: get out of the way, a spike is coming.

We tested whether that instinct holds.

We looked at every day VIX's RSI rose by at least 5, 10, 15, and 20 points in a single session, across 22 years of history. For each, we measured what VIX and the S&P 500 did next and compared it to a plain baseline. The result goes beyond having "no edge." It is the opposite of what the setup promises.

Condition	Same-day VIX move	VIX peak, next 20d
Any day (baseline)	n/a	+23%
RSI jump of 5+	+11%	+20%
RSI jump of 10+	+20%	+19%
RSI jump of 15+	+31%	+16%
RSI jump of 20+	+46%	+9%

Look at the "VIX peak" column. The bigger the RSI jump, the lower the forward spike. An RSI surge of 20 or more is followed by VIX going almost nowhere, well below the +23% you would get from a random day. The harder the RSI indicator fires, the more it predicts a fade, not a continuation.

Why? Because the RSI jump is the spike

Look at the same-day move. An RSI jump that size is, by definition, a big VIX up-day that has already happened. A jump of 20 comes on a day VIX rose a median of 46%. You are not catching a precursor to a spike, you are standing in the middle of one. And VIX is strongly mean-reverting: after an outsized single-day surge, the typical path is back down, not further up. The indicator is not early. It is simultaneous with the very move you hoped it would warn you about, and then it fades.