user63368: Let's take an example of Coinbase or Luno, who are their suppliers of bitcoins to be distributed to the buyers?

user63569: You have to think about it simply, its exchange service lets consider that they're exchanging potatoes for tomato instead of Bitcoin for money.
you've bought 50 kilos of potatoes from a farmer, a customer gave you 2 kilos of tomato for 1 kilo of potatoes and go on, the farmer here is mining pools which is the main source of bitcoins. 
So I would say Mining pools and Bitcoin sellers, but there's no specific answer to that question so I've marked it as Primary opinion based. 

63368: <p>Let's take an example of Coinbase or Luno, who are their suppliers of bitcoins to be distributed to the buyers?</p>
 63569: <p>You have to think about it simply, its exchange service lets consider that they're exchanging potatoes for tomato instead of Bitcoin for money.</p>

<p>you've bought 50 kilos of potatoes from a farmer, a customer gave you 2 kilos of tomato for 1 kilo of potatoes and go on, the farmer here is mining pools which is the main source of bitcoins. </p>

<p>So I would say Mining pools and Bitcoin sellers, but there's no specific answer to that question so I've marked it as Primary opinion based. </p>
