Comment by nearbuy | Hacker News Reader

Comment by nearbuy | Hacker News Reader

Parent Full thread

Information that requires 12 months to figure out isn't information that's available now.

Say you want to know the 400 trillionth digit of pi. We have all the information needed right now to know how to compute it. But you don't know what the actual digit is yet. The information isn't available and won't be until you set your supercomputer on it for some number of months. Having the information necessary to derive other information isn't the same as having the derived information.

If there is some information about a future stock price that could theoretically be computed after months of work, that's still not information that currently exists, and therefore is not currently reflected in the price. If no investors go to the lengths to get that information, it'll continue to not affect the stock price. It's not violating EMH because it's not information that exists yet.

That definition would mean that smarter investors, who can think faster and further ahead, get information faster. And therefore have information now that others do not.

That seems to be directly the opposite of the common definition of the EMH, which emphasizes how the market reacts to new information. And not how it produces information. For example in TFA:

"the market rapidly responds to new information"

Wikipedia starts the "Theoretical background" with an example on how information becomes widely available to all investors, not how one fast smart thinker generates it:

    Suppose that a piece of information about the value
    of a stock (say, about a future merger) is widely
    available to investors.

https://en.wikipedia.org/wiki/Efficient-market_hypothesis

The smartest, fastest investors are the ones who make a profit by incorporating their information into the stock price in the EMH. The stock price can't move on its own. Under the EMH, someone has to be the first to trade stock based on information so that the stock price reflects it. When they say "the market rapidly responds to new information", that means investors with the new information are buying or selling accordingly. It's not opposite at all.

How the information gets produced is irrelevant to the EMH. Whether it's obvious or takes hard thinking, either way, once investors obtain the information, they will trade based on it, and that will move the stock price.

>That definition would mean that smarter investors, who can think faster and further ahead, get information faster. And therefore have information now that others do not.

And that is trivially true

Reply on news.ycombinator.com