“It’s quiet,” as the clichéd allusion to imminent danger begins. “Too quiet.”

I talked about vol suppression in “There’s An ‘Invisible Hand’ Keeping Stocks At Records.” If you missed that article this week, go read it. You might learn something.

The figure below serves as a rather poignant reminder: The feedback loop between vol-selling and systematic flows can be quite tyrannical for those waiting on (and especially for those betting on) market fireworks. One-month, three-month and 10-day realized vol were all sub-10 handle headed into the weekend. Five-day was sub-five-handle.

Across vol control and CTA trend (with a little risk parity buying on the margins), total systematic exposure to US equities was dialed up by nearly $195 billion over the past three months on Nomura’s estimates. That’s the “massive” bid referenced in the chart header. The vast majority (88%) of that buying was attributable to the target vol universe.

The concern (intuitively) is that there’s precious little blood left to squeeze from this particular stone. And with systematics “all-in,” so to speak, it wouldn’t take much in the way of a vol expansion to trigger risk reduction.

“Spot equities positioning and vol behavior should be signaling caution, as the risk is asymmetric towards large mechanical de-leveraging into any vol squeeze catalyst, with VIX total vega-to-buy in a +10 shock now at 91% between ETNs and dealer options positioning,” Charlie McElligott said, noting that the target vol equity allocation’s 99%ile on a three-year lookback, while CTAs’ exposure to global stocks is 96%ile.

The chart header on the left, below, is one of the better market quips I’ve heard in quite a while. VIX call skew’s recently-bid as traders look to hedge a shock but this black swan’s a long time coming.

The figure on the right’s another way of visualizing the same futility. “With valuations at extremes, VIX call spreads remain somewhat popular for a possible convexity event but there’s just hilariously low VIX beta-to-spot,” McElligott wrote Friday. “Totally punchless.”

Still, ’tis the season, so to speak. So far, so good, but we’re not even halfway through September yet. There’s still plenty of time for this month to live up to its nefarious reputation.

The corporate bid — also known as the biggest source of demand for US equities — will roll into semi-hibernation beginning soon enough.

The figure above gives you a sense of the blackout window.

That won’t remove the repurchase impulse entirely. And large as it is, that source of demand’s not the only flow that matters. The point is just that a major source of support for the market will be partially hamstrung as we come up on earnings season.

“In addition to [the] risk that a smallish vol blip could create a much larger notional de-leveraging impact in light of so much length, the ‘invisible hand’ of corporate buyback demand [is set to] slowly dry up,” McElligott went on. “75% of the S&P [will be] in the blackout by October 6 and 75% of index market cap by October 2.”

So, again: There’s still more than enough time for September to make good on the seasonal threat.