neroden
Model S Owner and Frustrated Tesla Fan
Maximum-pain.com recalculates it at the end of the day every day, though sometimes they fail to get the data.Afaik, in option data, open interest data is only available end of day so that chart might move a lot each day as open interest changes.
Open interest data IS available real-time from many brokers, though you'd have to do the calculation yourself. Or just eyeball it -- the "open interest walls" are often more informative than max pain itself. If there are a HUGE number of $325 calls, the market makers would really prefer it if the stock closed below $325, and even if max pain is at $300 they might not really care much about whether it goes up to $320 if there are rather few calls outstanding between $300 and $325.