I haven't heard anything to suggest that the short sellers are forced to buy back the stock either. This is a stock has clearly caught public's attention, Once the hype cycle is over, why wouldn't it regress to the mean? Who's going to believe that the stock stays at this level over the long term?
Fun to talk about though. This is a very entertaining story.
If a short position goes hard against you the brokerage will make you to put up more collateral (money) and if you can't, then your only other option is to buy back some of your position, so yeah, short sellers can be forced to buy back stock.
The stock Signal spiked after Elon Musk said to use signal, has nothing to do with the app. A different Zoom spiked at the beginning of COVID. A lemonade company in 2017 put blockchain in its name and watched the stock price soar. Hertz went way up after declaring bankruptcy. I’m willing to bet this is clueless speculators.
Shorts borrow the stock for a time period. Let say you borrowed a stock that is $1 from me with the promise you will give the stock back end of the week + some interest. You sell the stock for $1 end of the week the price is $100 so you are on the hook for stock + interest. As the owner of the stock I will be more interested in getting it back and selling it for $100 rather than allowing you to give me the stock later by extending the loan terms when the price might drop.
There is, large market moves down over last few days are mostly due to hedge funds selling off longs to cover their shorts. If you look at GSVIP ETF (GS ETF for most loved names by hedge funds) it was down 4% yesterday. The short squeeze is real but I think funds are mostly out of it now (or ones remaining in the short have shorted at higher prices and in reasonable proportion of AUM). There's also a direct negative correlation between short interest and Russel 2000 performance over the last few days.
Fun to talk about though. This is a very entertaining story.