The difference between AMC and GME is the amount of trading volume. AMCs trading volume is higher. The difference between AMC/GME, and most other stocks, relating to a short squeeze (not gamma), is that AMC/GME, has been heavily shorted by big players for so long now, and the retail investor began to buy all the available shares of each of those stocks. I'm not sure other stocks had the right combo of being heavily shorted coupled with the retail investor buying up the supply. When the hedgefund makes a short bet against a company, they never anticipated the retail investor buying up the supply. When the retail investor buys up the supply, it begins a game of chicken with the the one shorting the stock. Those who short the stock have enough funds and them make a bet that they can have enough money to not get margin called, believing the retail crowd will eventually sell off their shares, which in turn the hedgefund scoops up, saving themselves. The retail investor is making the bet that the majority can hold onto the majority of the free float, holding onto the supply, longer than those shorting the stock can keep enough finances to prevent margin call. We believe there is just the right circumstances with AMC/GME, that makes it more ripe than any other stock for a short squeeze to take place. Also why you see media and articles every day only talk about why one should leave AMC or GME, "the short squeeze is over", and such because they know it's ripe for a squeeze, and they want it to be prevented.