Selling a used car is a useful analogy. If you know how much you want for your car, you can sell it yourself. If a willing buyer sees your advertisement, he may take the car off your hands at a price you both feel is fair. However, you might not be able to locate a buyer. If that is the case, you might decide to sell your car to a dealer.
The dealer then pays a price low enough for him to expect to turn a profit when he resells your car. The dealer’s knowledge of the car’s value comes from observing the used-car market. Ideally (for the dealer), he would like to offer you as little as possible, but if the offer is too low for your liking, you will simply look for another dealer. On the other hand, if your demands are too high to leave room to profit, the dealer will let you walk.
If you accept the dealer’s offer on your car, he will try to resell it at a higher price. Suppose the dealer is extremely lucky—the second after you leave the lot, a buyer enters, looking for exactly the car you just sold. Naturally, the dealer will sell it at a profit. The same car on the same day was worth less to you, the seller, than it was to the buyer.
Trading ETFs on exchanges works much the same way. If you as an ETF buyer are offering the same price that a different seller is demanding, the stock exchange is supposed to match up the two of you so that each of your orders can be filled. (However, exchanges have not always functioned this way, giving rise to periodic scandals and investigations. As a result, you should pay attention to the quality of your trade execution.)
However, suppose you want to buy an ETF at a time when a willing seller is not around. In that case, a dealer or specialist in a stock exchange offers to fill your order. Just as with a car dealer, a stock dealer transacts with you only at a price that allows him to make a profit. With the advent of electronic trading, you (through your broker) can look for the best price available for the ETF you want on more than one exchange. This is analogous to shopping around for the best price at multiple car dealerships.
If the dealer sells you the shares you want, he immediately tries to repurchase them from someone else at a lower price. If you turn around and try to resell your shares to a dealer (or specialist, or market maker), you receive less than you paid, even if the market has not moved one iota in the interim.
The price you pay to buy shares at the lowest available price is called the asking price, or ask. The price you receive when you sell shares at the highest available price is the bid. As with cars, stock dealers stand ready at any time to sell you shares at the ask price or to buy shares from you at the bid price.
The difference between the price you have to pay to buy shares and what a seller would receive to sell shares is called the bid-ask spread. The bid-ask spread is no less a cost to you than a broker’s commission, despite being less visible. But to the unwary investor, the bid-ask spread is a hidden cost. Before you decide to buy an ETF, you should ask your broker for both the bid and ask so that you can get a feel for the cost per trade.
Read More : ETF Investors Have Hidden Costs Through the Bid-Ask Spread
