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This seems like a silly point. Are markets more efficient in the infinitely long run than an individual who tries to identify the "correct" price? Quite probabl
by matthewdgreen 6y ago
This seems like a silly point. Are markets more efficient in the infinitely long run than an individual who tries to identify the "correct" price? Quite probably. Does the current stock market price at any given moment possibly reflect the herd mentality of a bunch of jumped-up plains apes (or the injection of a huge amount of funds by a central bank), rather than representing the future expected earnings of a given asset? Also extremely likely.
The performance of the markets during the lead-up to the pandemic was absurd. It wasn't just the top-line market prices that were wrong: the obvious hedges, like Put options, were all massively mispriced, to the point that even banks started warning about it. This eventually corrected, but the correction itself was extremely painful. Now the Fed is injecting dollars in order to help "correct" the correction, with unknown long-term effects. (I don't know what the EMH has to say about prices under this regime.)
Anyway, "the EMH is wrong" is an absurd simplification of the problem. The real objection here is that asset prices may be right on average, in the long-enough term, but are prone to huge over-confidence bubbles and corrections that can wreak havoc on the actual human beings, and possibly lead to suboptimal economic outcomes when prices are used to direct investment.
- JumpCrisscross 6y ago> obvious hedges, like Put options, were all massively mispriced As a former options market maker, this wasn’t obvious. That said, every time volatility snaps one tends to find a cohort of investors who got burned blaming the Fed.
- rmrfstar 6y agoEMH is a mental-model of equilibrium, and is useful when used that way. Financial systems have multiple equilibria [1], so EMH "violations" come in two flavors: 1. Small deviation from equilibrium. This is where Renaissance Technologies hangs out. 2. Market herd expects the wrong equilibrium. This is where Nassim Taleb hangs out. On the scale of single years, 2 happens so rarely than you can't get statistically significant measurements. So, we end up with endless philosophical debates about whether EMH is "true". [1] https://en.wikipedia.org/wiki/Diamond%E2%80%93Dybvig_model https://en.wikipedia.org/wiki/Diamond%E2%80%93Dybvig_model
- Gibbon1 6y ago>"the EMH is wrong" The EHM is economists being dimly aware of the third law of thermodynamics, but not being smart enough to make any actual sense of it.