what would happen if people were to convert their currencies to Bitcoin and withdraw them from the exchanges simultaneously? Or let's say that nobody withdrew the Bitcoins from the exchanges, would it not be an extremely volatile situation for both exchanges and Bitcoin in general that there were more Bitcoins in theoretical circulation than actual existence?
pre-condition: userA deposited BTC and placed sell BTC order (seller)
you (buyer) convert your fiat to Bitcoin in exchange = buying BTC, deposit/inflow of fiat to exchange
userA withdraws his fiat from exchange, after he sold his BTC to you, withdraw/outflow fiat from exchange
in what
normal case would be
"there were more Bitcoins in theoretical circulation than actual existence?"it would ONLY be the case if the exchange lied/cheated about the bitcoin amount he has for trade
exchange = swap , there could be no more/extra bitcoin amount in exchange than the actual existence
the same thing applied in general terms, trade outside exchange can happen based on actual bitcoin and fiat in existence
in the case for bank, Brennus101 explained it well except small mistake
Banks and fiat are completely different. Banks use something called fractional reserve banking, which means they lend more money than what is deposited by customers in their accounts. This means that if all customers were to attempt to withdraw their funds, the bank would collapse. An exchange is not supposed to work like this, although in principle it could. However, I would regard an exchange which operates like this as a scam. It would be like a stock exchange selling you stock they don't actually have!
https://en.wikipedia.org/wiki/Fractional-reserve_bankingit doesn't mean they lend > deposited amount... how could that be logically?
but at any given time, bank holds cash currency < total deposited amount
fractional reserve banking means the bank is required by law
to hold only fractional (% amount) of total deposited amount in cash in the bank
which most of the deposited amount would be used for lending or investment fund
so basic equation (excluding cost, profit and etc) roughly the bank would hold
the total deposited amount = available cash amount for transactional + outstanding loan amount