Earlier quoted context omitted.
The efficient market hypothesis would like a word with you.
I just googled that to inform myself. > The efficient market hypothesis in financial economics that states that asset prices reflect all available information https://en.wikipedia.org/wiki/Efficient-market_hypothesis The efficient market hypothesis seems easily disproven with a number of modern examples. Climate change for example - there is significant information available, but markets act as though the information…
I think of markets as a real-time implementation of information theory. There are certain facts that exist, and they are not all known although they may be discoverable. As they become known, or are considered more heavily, those facts bleed into market prices.
In this view, the market is a collective model of the world and thus it is not reflective of all true information.
The model overvalues the confidence and beliefs of people who have money. Sometimes, these people trade stock of companies that deal more with lower-income individuals. Their knowledge of those companies is limited, but over time they may converge toward a better understanding.
Also, sometimes there are errors in interpretation of easily discoverable facts. After 9/11, interest rates went down, but the market didn't price that into auto sales despite 0% interest auto loans being offered to the market.
The market is a model that perpetually converges to a set of facts that are constantly shifting. There is always a gradient (like osmotic pressure) between the model and the reality it represents, so there is always some motion in the market.
And there is always a set of expectations about the future that must be reflected in the model. These expectations have a wide variety of distributions, some are gaussian, others are bimodal, etc. That adds another layer of complexity in getting the model to converge to an appropriate expected value.
Not only that, but several different assets are interlinked. For example, if you buy a large block of call options on a high-volatility name, the market-maker will probably buy stock as a hedge. But in the absence of an upcoming event, he will buy patiently over the course of several trading days in order to minimize the price change resulting from his purchase ("delta impact"). So the market knows that the market-maker traded options, but he has an incentive to hide his hedging activity from other market participants so that they don't front-run him. As a result, it takes time for the purchase of the delta via options to be reflected in the underlying stock -- even though the options trade was printed on the exchange immediately and publicly.
Even if markets were efficient to known information, their price moves do not arrive at equilibrium instantaneously. There is an information gradient -- a kind of osmotic pressure between what is truly happening and what is reflected in the price -- that takes time to normalize itself.