A week ago Friday (10/10/25) there was a crypto crash. Not huge, but not small. Bitcoin:

Ether was also hit.

The proximate cause was the most recent Trump tariff spasm. But that was just the spark. The initial down move triggered classical self-reinforcing crash dynamics. And the crypto market structure is arguably uniquely vulnerable to such events.

As I’ve written for years and years, (a) tightly coupled systems are vulnerable to catastrophic collapse, and (b) a wide variety of factors produce tight coupling in these markets. The most important of these factors is marking to market and variation margin.

And this dynamic is particular fraught in crypto. Positions are marked to market at a very high frequency. Moreover, the resulting margin calls occur at the same frequency. That frequency is so high that margin breaches result in liquidations of positions (“auto liquidations”) because there is no time to replenish collateral. These liquidations exacerbate price movements, creating a positive feedback mechanism–and positive feedback is almost always a bad thing in financial markets.

But it gets better! Risky positions are sometimes collateralized with . . . risky collateral! Specifically so-called “stablecoins.” I say “so-called” because stability is aspirational rather than real, especially for a new variety of “stablecoins” implicated in the 10/10 event, like USDe.

Whereas traditional stablecoins like Tether are supposedly backed by high quality, low-risk dollar assets (and the recent “Genius Act” will reduce any uncertainty about that), USDe is “backed” by both dollar assets and–wait for it–crypto. So what is the lithium that keeps USDe “stable”? Hedging using perpetual futures.

No. Seriously. Yeah, because hedges are always perfect, right? Here’s the only perfect hedge I’m aware of:

So in reality the “stablecoin” has basis risk, the basis being the difference between the price of the crypto collateral and the perp futures.

Arbitrage is supposed to keep the basis small with little volatility. However, if you look at data, e.g., the spread between BTC and BTC perp futures on Coinbase, you will see that there are frequent and large basis movements, often as big as 1 percent.

Moreover, USDe is traded on multiple exchanges, and the prices can diverge. Again, arbitrage is supposed to keep those divergences small and of short duration, but the market moves faster than arbitrage: given the frequent revaluing of positions and collateral, even a very brief price divergence can trigger a self-reinforcing spiral before arbitrage can close the gap.

On 10/10, Coinbase used the price of USDe on its platform to market collateral to market. But that exchange is not the primary USDe platform, and is therefore relatively illiquid. So forced liquidations of positions on Coinbase due to the price move and marking to market led to liquidations of USDe collateral which pushed downward pressure on the Coinbase USDe price which led to more positions being undercollateralized which led to those positions being liquidated. And this all happened faster than the speed of arb. Rinse, wash, repeat.

Can you say wrong-way risk? I knew you could.

The industry cope is to say “well ackshually if Coinbase had used the USDe price on more liquid exchanges as its USDe ‘oracle’ this wouldn’t have happened.”

Maybe. But irrelevant. What happened on 10/10 was a “normal accident.” Normal accidents result from a sequence of events in a tightly coupled. complex system. Accidents are “normal” in such systems because there are many, many, many possible sequences that can trigger accidents. Meaning that even if this particular sequence is eliminated by referencing prices from the most liquid exchange, many, many, many other such sequences will remain.

The underlying “cause” of such events is the very nature of the system itself. The reason crypto is particularly susceptible is the tight coupling due to frequent marking to market and high leverage. Those factors remain.

The crypto system is acutely vulnerable due to another structural factor–the fragmentation of trading. As I’ve frequently written, crypto market structure is puzzling. The centripetal force of liquidity typically results in the concentration of trading on a single platform. Crypto, in contrast, is traded on multiple exchanges, with several have a fairly large market share.

This fragmentation increases the number of connections and therefore the number of possible paths by which a destabilizing shock can spread. And referencing prices from other exchanges to value positions or collateral on a given exchange creates more such interconnections.

In brief, a shock–a price shock, or an operational shock–on one exchange can impact other exchanges. These shocks can trigger the destabilizing auto liquidations.

“Too big to fail” is not the right description of the crypto market. Instead, “too interconnected and tightly coupled and complex to succeed” is more accurate.

It must also be noted that the factors that make the crypto market systemically fragile make it unduly susceptible to manipulation which can in turn trigger systemic crises.

One of the oldest strategies in the book is “gunning the stops.” The play being that if you force prices to hit stops order triggers, that will induce trades that move prices further in the same direction.

In crypto, the game is “gunning the liquidations.” The idea is the same. Trade like a whale to push the price in a particular direction. If the move is big enough, that will trigger liquidations that move the price further in that direction. And since some collateral is risky, there is another way to manipulate–bash the collateral.

Given the high leverage and high frequency marking to market, the necessary push isn’t that big–maybe a dolphin can do it. And as shown on 10/10, and as discussed above, once the price moves begin they can trigger a crash.

It is also disturbing that crypto exchanges can profit from liquidations. Conceivably this could provide an incentive for the exchanges to manipulate themselves. But even if that’s not the case, the fact that they can profit from destabilizing manipulations, and instability generally, means that they have a weaker incentive, and perhaps a positive disincentive, to prevent/deter manipulations or big price moves.

In sum, crypto market structure is crapto. It has all of the inherent vulnerabilities of markets, but on meth. Supposed “innovations”–like near continuous marking to market and unstablecoin collateral–exacerbate these vulnerabilities. As does the fragmentation.

All meaning that it is inevitable that you will see this movie again.