The problem I have is that this seems to be another red flag that we are in the late stages of a bull market. The point where, at least according to folk wisdom, the least sophisticated investors enthusiastically enter the market.
See footnote 3. "This does not necessarily mean a lot of people are doing evil illegal nefarious naked shorting! Really, I promise! There is no special limit on shorting at 100% of shares outstanding! Here is an explanation of how options market makers (discussed below) are allowed to short without a locate, but I want to offer an even simpler explanation. There are 100 shares. A owns 90 of them, B owns 10. A lends her 90 shares to C, who shorts them all to D. Now A owns 90 shares, B owns 10 and D owns 90—there are 100 shares outstanding, but190 shares show up on ownership lists. (The accounts balance because C owes 90 shares to A, giving C, in a sense, negative 90 shares.) Short interest is 90 shares out of 100 outstanding. Now D lends her 90 shares to E, who shorts them all to F. Now A owns 90, B 10, D 90 and F 90, for a total of 280 shares. Short interest is 180 shares out of 100 outstanding. No problem! No big deal! You can just keep re-borrowing the shares. F can lend them to G! It's fine."
I guess I'd just prefer they use call options to cover the shorts instead of borrowing. No leverage or multiplier effect there. Gets too high, just execute the call. Am I also missing something there?
To short a share, you must borrow and sell it.
If you buy a call, you're long. You could write a call and then you'd have short exposure, indeed, but on the wrong side - you lose on the way up, while you want to win on the way down. So, you could buy a put - that makes you short, winning on the way down. However, now the entity that wrote the put is long, and will generally cover their exposure by - shorting. No magic bullet there.
At least in theory, if retail investors buy up the stock, some of the institutional investors who own it, and who have lent it out, will sell it to them. This could mean that they recall lent stock. As this happens, shorts might have to compete to buy the stock. Equally, as the price gets higher, shorts might have to cut their losses, which also means buying back the stock. If the people buying it now don't sell it and don't lend it they will withdraw a lot of the supply.
Obviously not going to happen with GME or anywhere realistically, but I'm just curious how that would be handled.
The fee could be quite punitive, or fairly trivial depending on the market. In some markets failure to deliver would be a very big deal and multiple could lead to some sort of disciplinary action. In other markets they might be commonplace for whatever technical reason, and everyone expects that they will happen, just tries to avoid them because of the fee.
There are various theories that in certain markets everyone fails to deliver all the time and it means that there isn't enough of whatever to meet all the obligations. I can't really comment on how much they make sense.
That still doesn't explain how you know folks aren't naked shorting. Maybe you can read the trades?
Stock borrowing is very very commonly done and renewed per-day, in the vast majority of situations this works fine.
B short sells to C.
C lends 1 share to D.
D short sells.
200% of outstanding shares are shorted.