Soichi Hayashi · blog

What the market actually prices in

CategoriesFinance

Every sharp market move seems to trace back to something nobody saw coming — a sudden war, a policy shock, some discontinuity with no precedent to price against. That’s the part of market behavior I keep coming back to: the future isn’t unknowable because we’re bad at analysis, it’s unknowable because the thing that actually moves prices is, by definition, the thing nobody could have modeled in advance.

Which is why I’m skeptical of any strategy built on watching how the market behaved last time and assuming it will behave that way again. If a pattern is visible enough to spot on a chart, or explainable in a five-minute video, it’s visible enough that someone else has already traded on it — and once enough people do, the pattern gets priced away before it’s useful. History doesn’t repeat cleanly enough to trade on casually; it mostly just rhymes enough to make a convincing story after the fact.

But “you can’t trade on a hunch” is different from “there is no edge.” Real, persistent inefficiencies do exist — patterns and premia that survive being known about, either because they only pay off if you can hold through long stretches of being wrong, or because exploiting them profitably takes more infrastructure than any single chart or backtest can capture. Finding and harvesting those is a fundamentally different exercise than pattern-matching a chart. It takes rigorous, systematic, data-driven research: testing an idea across decades of data and dozens of markets, controlling for how a signal decays once too many people find it, and sizing every bet so that being wrong on any one of them doesn’t matter much.

That’s the actual case for active management done well — not someone with a strong opinion about where the market goes next, but a process built to separate real, durable signal from noise at scale, and to keep doing that as the noise itself adapts. It’s also exactly why I’d trust that kind of process over a hot tip from a video or a confidently-written blog post — including, a little uncomfortably, this one. The distance between “I noticed a pattern” and “I found something real” is a lot of rigorous work, and most of us, myself included, aren’t equipped to do that work on the side.

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