Bitcoin users get Bitcoins by exchanging them for fiat at exchanges but where do the exchanges get bitcoins from ?
This question came to my mind after frequent cases of YoBit's Signature Campign wallet getting dry !
Basically, exchangers get their coins from either miners, traders, contacts, etc. They can just ring up people and buy from them whenever they run low on bitcoin inventory. They have some sort of a wallet/s to check whether their bitcoins needs restocking or immediate selling.