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system
does longterm investment in index funds still make sense in a reality of massive algotrading?
user
why wouldn't you expect a long-term profit?  say you buy 100 shares of company x, selling for$1/share today.  you hold it for 20 years, after which it's worth $10/share (in inflation-adjusted dollars).  so you've made a profit, only making two trades (buy & sell).  what the algorithmic traders have done with short-term trades during those 20 years is irrelevant to you. now expand the idea.  you want some diversification, so instead of one stock, you buy a bit of all the stocks on whatever index interests you, and you just hold them for the same 20 years.  how has what the short-term traders done in the intervening time affected you?
assistant