The issue with small exchanges is that the number of sell orders could be very small. This means that if an investor wants to buy even $500 worth of currency, then this could move the price. High liquidity means that investors can buy their chosen coin in one go and at the same price. OKEx has the second highest liquidity in the world and this makes buying virtual currency easy there. The OKEx exchange has spent its formative years establishing itself in the Asian market.