If there are two shares in circulation, then why isn't that reflected in market cap? No, there is still one share. What happens when you loan out a share is that you own but don't possess it anymore. Just like renting out a book to a good friend. There are not suddenly two books now. There is still one book. You own it, your friend possesses it.
Market cap is based on outstanding shares, rather than shares in circulation.
What do you call a good friend who sells the book you rented to him? What good friend calls
you if before renting him a book you insist on cash collateral in the amount
greater than value of the book?
Seriously, though, the reason that there is only one book is because you can't sell the book that you lent to your good friend. Your good friend can't sell a book rented from you neither. So analogy does not work.
I hold shares of TSLA in margin account at Fidelity. Fidelity is free to lend all my shares to a short seller, who sells them to a third party. I can sell my shares. The third party can sell shares bought from the short seller as well. Short selling increased shares in circulation (regardless whether I sell shares that Fidelity lent or not). That is why short selling increases liquidity. Welcome to the virtual reality.
I have a puzzler (all numbers at the end of Q2):
There are 148.7M outstanding TSLA shares.
There are 100.5M institutional shares (per Nasdaq page)
There are 31.1M shares owned by Elon.
There are 31M shares sold short
Neglecting shares owned by other insiders, how many shares are held by others (retail)?
A. 148.7 - 100.5 - 31.1 = 17.1
B. 148.7 + 31 - 100.5 - 31.1 = 48.1
P.S. This is very good discussion, but just to maintain it's quality, can we agree not to use word "No"?