I use support/resistance ideas regularly in my trading with individual stocks. But does trading using support/resistance make sense with an ETF where the âstockâ is based on an index of dozens of underlying stocks? Mathematically this makes no sense to me. Why would dozens of stocks going through their own indivicual S/R levels piece together into a magical index-level S/R? I see people discuss it quite often, so I figure that there has to be a good explanation. Is this because the ETF, through large-institution arbitrage, can actually exert pressure on the underlying stocks and make the S/R âstickâ so to speak?