Or perhaps its market makers taking profits?

Think about it - I own a shop and buy a tomato for $1.00, now I need to sell for $1.35

In the case of market makers its a bit on the reverse side - I sold a tomato for $1.35 now I need to repurchase it for $1.00


Also read the top post - something about supply and demand and all that jazz.... uhm If someone is buying a BTC does that warrant demand > supply because to actually demand and buy 1 BTC there has to be an equal supply of 1 BTC sold... so demand always equals supply??