A Random Walk and Efficient Market Theory are misunderstood and misrepresented. People equate efficient market with perfect market, meaning the market "knows"

A Random Walk and Efficient Market Theory are misunderstood and misrepresented. People equate efficient market with perfect market, meaning the market "knows" the right price. All that efficient market theory states is that information is communicated efficiently, not that the information is correct. Other bubbles would never happen. Proponents state that prices are only correct in the long run. Malkiel (author of A Random Walk) advocates whole market index funds simply because you cannot know what information is correct and beating the market is a fool's errand. Again the case in point being the irrational run up in tech stocks not based on fundamentals but based on the greater fool theory. Information as pricing was communicated effectively but the information is not guaranteed to be either correct or rational. The stock market is a weighing machine not a voting machine - Benjamin Graham. However, I do enjoy Cuban's take on this as he's been there and down that. I think he could write a great book at some point.