As a previously bulletproof equity market careened lower into the US afternoon on Friday, CNBC asked the only question that matters when stocks are down more than half a percent: “Time to buy?”

I can’t answer that question definitively (and neither can anyone else), but my best guess is “no.”

It’s true that discretionary positioning is nowhere near aggressive, which is to say “professional” investors are if anything under-exposed to a rally which this week minted a 30th new all-time high since the S&P reclaimed its February peak in late-June.

But systematic cohorts, including and especially the vol control universe, are sitting with maxed-out stock exposure, and that’s just waiting to tip over in the event of a sustained vol expansion. If the daily distribution of spot outcomes widens — colloquially, if the market starts to “move around” and the swings are sustained on a close-to-close basis — those strategies will be a significant source of unemotional supply. They’ll de-risk mechanically.

At the same time, it’s important to remember that leveraged ETFs are sitting with record AUM. Those products’ rebalancing needs have to be taken into account, and they aren’t trivial. In the same vein (i.e., in the context of downside convexity potential) dealer hedging flows could be gas on the fire, particularly if panicked market participants try to hedge into the selloff and spot keeps falling, moving down into put strikes dealers are newly-short, forcing market makers to sell futures into the hole.

I went over all of that on Wednesday in “A Half-Trillion Dollar Sell Flow (Hypothetically).” That half-trillion figure obviously doesn’t apply to a pedestrian ~2% down move — i.e., Friday’s selloff wasn’t deep enough, nor the vol spike steep enough, to trigger anything close to a worst-case — but the dynamics are the same.

The figure above, from a late-afternoon Charlie McElligott note, gives you a sense of things. Between the leveraged ETF rebalance, dealer hedging and vol control, Friday’s tariff scare had the potential to manifest in a near $90 billion mechanical “sell” impulse assuming the 2% downside move held.

As McElligott wrote, that’d likely snowball into a ~$150 billion mechanical “event” in the presence of a 3% one-day downdraft.

This is always a battle between, on one hand, the learned response function — i.e., the classical conditioning which demands any equity dip, no matter how trivial, be bought in an environment where competition for “dip alpha” is fierce — and, on the other, the scope of the mechanical de-risking and the assessed odds that the “shock” catalyst lasts longer than a day.

The catalyst on Friday was Donald Trump’s renewed tariff threats against China, but there are two aggravating factors: The collapse of the LDP-Komeito coalition in Japan and the onset of Russ Vought’s layoffs in D.C.

Between them, those three risks (US-China tensions, Japanese political turmoil and potentially thousands of new layoffs across the US government sector) may be sufficient to temporarily override the Pavlovian conditioning which says all equity dips are buying opportunities and occasions to sell rich vol.

“The dicey thing right now is that folks are trained to fast-monetize hedges into these types of vol squeeze / spot selloff moves,” McElligott said. “The problem,” he went on, writing with about an hour to go before the closing bell, “is that hedge monetization today thus far hasn’t been much more than a speed bump with regard to stifl[ing] the spot selloff, as it seems the mechanical flows are simply overwhelming the muscle memory.”