There are two stock markets. One is made of cash flows, discount rates, earnings, margins, inflation, debt, productivity, recessions, and all the other boring things that eventually matter. The other is made of beliefs. Not survey beliefs or what investors say on television. The marginal beliefs embedded in prices.

Most of the time, we implicitly assume these are the same market. They are not.

Aizhan Anarkulova, Scott Cederburg, and Yi Zhou’s paper, The Stock Market’s Two Truths: Subjective Beliefs and Objective Reality, is worthwhile because it tries to separate the two. The authors develop a framework that infers the representative investor’s subjective beliefs from market returns and compares those beliefs with objective cash-flow and discount-rate news. They conclude that investors substantially underreact to fundamental news. On average, prices initially incorporate only about 30% of an objective cash-flow shock, and full adjustment can take up to four years.

That is a big claim. It does not say the market misses everything. It says prices contain beliefs, and beliefs can move much more slowly than reality.

This is the useful middle ground between naive EMH worship and lazy behavioral-finance sneering. The market is not a perfect voting machine that instantly adjusts. But neither is it a room full of idiots buying based on patterns on charts. Prices are set by investors trying to interpret noisy information under uncertainty. Sometimes they are too slow. Sometimes they are too optimistic. Sometimes the gap between what is believed and what is true can persist long enough to matter.

The paper’s ideas are particularly interesting around recessions. The authors find that underreaction to fundamentals is more pronounced in pre-recession periods. Prices can rise before a recession because investors remain optimistic about future cash flows even as objective fundamentals are deteriorating. Then, as the recession unfolds, the belief-reality gap closes and prices crash.

That is not the usual simplified story of a crash. The simple version says investors are happy, then suddenly they are not. This paper suggests something more precise, in that reality weakens first and beliefs adjust later. The crash is not merely the arrival of bad news. It is the late recognition of bad news that was already there.

That distinction matters. If markets reacted to new information immediately, there would be little to do except provide liquidity, bear risk, or exploit tiny structural frictions. But if beliefs adjust slowly to fundamentals, there is room for trend, macro momentum, earnings drift and other slow repricing effects. The edge is not that you are smarter than everyone else. The edge is that the market’s belief-updating process has inertia.

This also changes how we should think about “priced in.” People use that phrase too casually. A recession can be discussed constantly and still not be fully priced in. An earnings slowdown can be obvious and still not be fully reflected in expectations. Awareness is not the same as adjustment.

Everyone can see the same thing and still fail to update enough. Markets do not just need information. They need belief revision.

The paper’s method matters because surveys are an awkward way to measure beliefs. Investors say things for many reasons. They may be talking their book or just repeating the consensus and trying to sound smart. Prices, by contrast, are “skin in the game”. They are beliefs with money attached. The authors try to infer expectations from return dynamics rather than relying only on what investors claim to expect.

This has a direct implication for investing. Many strategies fail because they confuse signal with immediate catalyst. A fundamental signal can be right and still take years to work. A macro signal can identify deterioration long before the market cares. A valuation signal can be correct while price continues in the wrong direction. This is not a contradiction. It is the cost of trading against beliefs.

The hard part is that slow belief adjustment cuts both ways. It creates opportunity, but it also creates pain. If investors incorporate only a fraction of fundamental news initially, then a person who sees the full implication early may look wrong for a long time. The market can remain optimistic after fundamentals turn down. It can remain pessimistic after fundamentals improve. Being right about reality is not enough. You also need a view on the speed at which reality will infect prices.

That is why pure valuation trades are so difficult. Valuation often tells you something about long-run reality, but it says much less about the timing of belief adjustment. Momentum has the opposite virtue. It does not need to know why beliefs are changing; it only needs to observe that they are. The cleanest strategies often combine the two: fundamentals to identify the direction of reality, price action to confirm that beliefs have started to move.

The recession result is a particularly good example. If fundamentals are deteriorating but prices are still rising, shorting immediately may be miserable. The belief-reality gap can widen before it closes. But once the market starts to revise, the move can be violent because several periods of ignored information get compressed into one repricing. This is why late-cycle markets often feel so stupid on the way up and so obvious in hindsight on the way down.

There is also a useful lesson for risk management. If crashes partly reflect delayed belief adjustment, then risk is not only about volatility. Risk is also about accumulated denial. A calm market can be dangerous if prices are built on stale optimism. Low realized volatility does not prove that fundamentals are fine. It may only prove that beliefs have not moved yet.

Sometimes price is truth. Sometimes price is merely the market’s current story about truth. The investor’s job is to know which one he is dealing with. No one (sensible) said this was easy.

Disclaimer

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