Hacker News new | past | comments | ask | show | jobs | submit login

> all public information is quickly priced in

Yeah this theory is bollocks. Priced in by whom, Wall St or Redditors? This theory may have been relevant before retail investors were a large force, but now it's irrelevant. I mean, if it worked, you'd never have meme stocks.




In defence of the efficient market theory, retail investors can be just the wisdom of the crowd. Meme stocks are a rare exception.


That assumes the crowd has wisdom/some information that should be reflected in stock prices, instead of just buying based on FOMO/emotion


If you look at actual cases of "meme stocks", they happened because the meme factor could actually help the underlying business. GameStop was one famous example of that - if a meme makes the company more popular with the general public, that translates to better forecasts for business outcomes.


Citation needed. If that were the case, meme stocks would have been embraced by Wall St instead of heavily shorted (IIRC BB & B was) because a pump and dump doesn't in fact materially improve the underlying business.


economic and finance theory is based on some clear assumptions. if those assumptions are violated, the theory predicts that the theory cannot predict.

"meme stocks" attract a small amount of capital (, large only) to a small number of stocks whose price becomes inflated. Given the nature of memes, this will rarely happen to the whole market. If you owned a broad index fund, your portfolio would inflate along with the meme stocks, and it will deflate along with them later. If it turned out that GameStop was an actual runaway hit, you would participate in it. If it turned out it was just a fad, you participate in that also. There's no place in this story for broad index funds to be a bad idea. Investing directly in the meme stocks carries a huge amount of diversifiable risk, and the market rewards risk, but not diversifiable risk.

I said "rarely" to the whole market above because one could consider the .com boom a whole market meme. But you would have been worse off if you stayed out of the market through that bubble.


Every theory is based on assumptions. I'm saying the efficient markets hypothesis is less relevant now, not CAPM.




Join us for AI Startup School this June 16-17 in San Francisco!

Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: