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there are good arguments for why it should work. Basically many professional market participants trade options not as a directional strategy (buy calls when you are bullish, puts when you are bearish etc) but trade the gamma of the option. That means if they are long gamma (i.e. long options) they will sell stocks to rebalance their delta when the stock price goes up and buy stocks when it goes down. At expiry the gamma (which is the change in delta over stock price change) is extreme as the delta goes from 1 to 0 if the stock price crosses the strike price. So said gamma traders will sell large amounts of stock if the share price goes above the strike price and buy large amount of shares if it drops below. As a result they 'pin' the share at the strike price if the open interest is large enough. Now the caveats why this often doesn't work: For every long option position there is someone else with a short position - so the question is how the open interest is distributed between 'gamma hedgers' and naked option positions (investors who hold option positions without hedging/rebalancing their delta). So if a large institutional player (say a mutual fund) that doesn't rebalance delta sold a chunk of options to a liquidity provider (bank, market maker) than the gamma hedgers are long and there is no offsetting other side (on the stock supply/demand). If the position is between gamma hedgers then they neutralise each other buying/selling shares for their delta rebalance and the effect is MUCH smaller. I've traded options as a 'liquidity provider' at a bank for many years and went trough many expiries so that was a big topic to look at. I would say more often than not shares DO pin on large open interests but there are still many occasions where they don't (I would say the ratio is something like 55/45 - maybe a touch higher) and I found it hard to base a reliable trading strategy around that