Bid-Ask Spread is the spread between two price levels at which one can purchase or sell a currency or security to/from a market-maker or another service provider at a given time. Consequently, the bid-ask spread can affect the price at which a purchase or sale is made – tighter spread meaning better terms for the customer. Bid-ask spread is determined by multiple factors depending on what cost and charges are built into the quotes as well as the underlying liquidity of the currency or security.