Select ALL of the following that are true of the bid-ask spread:

1. The percentage of bid-ask spread in major currency pairs ($) is smaller than the average bid-ask spread for US mid-cap stocks.

2. From a trader's perspective, the bid-ask spread is the difference between the highest quoted bid and the lowest quoted ask

3. The bid-ask spread may widen due to increased risk and volatility in markets.

4. The percentage bid-ask spread is calculated as the bid price minus the ask price divided by the spot price.

5. The bid-ask spread provides compensation to market-makers (dealers) for the provision of liquidity.