Bid Ask Spread

Bid ask spread sounds somehow complex, but it’s not. Let me explain it to you with some optional details and examples.

What Is The Bid Ask Spread?

The price difference between bid and ask defines the so-called spread. If the bid price is $200 and the ask price is $202, then the spread bid vs ask is $2. Getting back to buying and selling with market orders means, in this case, that you buy or sell your stock accepting that you may get a $2 worse order execution than you expected.

Let’s say that the last price you saw was $200, the bid is $200, the ask is $202, and you order 100 shares market. In this case, your order probably gets filled for $202, which is $2 worse than you expected. This difference between the price you wanted to get and the price you finally got is called slippage. The higher the spread of stock, the higher your slippage can be.

How To Buy at Bid or Ask Price

The order book consists of buy and sell orders. Buyers who transmitt buy limit orders, create the bid side. Sellers, who send sell limit orders to their broker, create the ask price.

There is only a trade, if the buy and sell order match at the exact same price.

Example: The order book looks like this:

  • Best Bid: 500 shares @ $100.00
  • Best Ask: 300 shares @ $101.00

As explained above, if a buyer places a market order, then his trade automatically gets executed at the best possible ask price. Let’s say the buyer wants to buy 100 shares with a market order, then based on the order book above, the order gets executed for 100 shares at $101.00.

But, if the investor wants to buy shares at the bid, then he typically intends to get the shares at a lower price. So, for example, if he wants to buy the share for $90, which is right now far away from $100, then the investor can put a limit order in the system at $90 and gets only executed if the price goes that low until his order expires (you can limit the order duration until the end of the day, month or without expiration date, etc.).

If a buyer places a limit order, he limits the price to what he is willing to buy a share. If that limit is below the best available ask price, then the order gets to the order book but does not get executed since there is no matching sell order.


Order Book before new order:

  • Best Bid: 500 shares @ $100.00
  • Best Ask: 300 shares @ $101.00

Now the new investor steps in and inserts a limit order of 100 sharres at $100.50.

Now the order book looks like this:

  • Best Bid: 100 shares @ $100.50
  • Best Ask: 300 shares @ $101.00

Since the bid and ask do not map, the order remains open.

If the buyer increases his bid to the best available asking price of $101.00, the order gets executed. Also, if another seller comes in and sells at market or for a limit of $100.50, then the order gets executed too.

Still, keep in mind that the price is only one component. The number of shares is the other one. If fewer shares are available at the price you want, then your order gets only partially filled, while with a market order, the order typically gets always filled, but you don’t have control over the price.

Bid vs Ask

Most brokerage trading platforms come with the standard settings of displaying the stock symbol, last price, change in % and change in $. Retail investors sometimes conclude that the last price they see in the trading platform is also the price for their stock. It is important to understand that there is a big difference between last price and bid vs ask.

Last Price

The last price shown in your trading platform reflects the previous transaction price, the last trade if you will.

Trades are executed via a broker on exchanges like Nasdaq.


If you are a buyer, you want to buy for the best possible price (as low as possible). If you use a limit order, you become responsible of creating a bid in the order book.


If you are a seller, you want to sell for the best price possible (as high as possible). If you are using a limit order for selling your shares, you then define the ask with your limit price to sell shares for that price with your defined number of shares. The order book collects, in this case, all the offers from sellers on the

How a Trade Gets Executed

There are 3 ways of how an order can be executed. If a buyers limit order matches a seller’s limit order in price and number of shares, those market participants’ orders make the deal. The buyer gets what he wants, and the seller gets what he wants for exact the parameters they used for price and number of shares.

If the limit order prices and the number of shares do not match, the orders remain in the order book as long as it takes until two parties find together.

As I mentioned above in bid vs ask, there is also a way to place an order for a specific amount of shares but without a limit. Those orders are called market orders. Market orders always get filled for the best possible price.

If a buyer wants to buy 1,000 shares of the company XYZ market, the order gets matches with the best possible seller prices on the ask side of the order book. That means that the market order from the buyer hits the limit orders from sellers. The buyer never knows what price he gets. He only knows that he gets the best possible price for the shares he wanted to buy.

If a seller wants to sell 1,000 shares of a company XYZ market, his order is matched with the best possible buy limit orders from buyers in the order book on the bid side. So if the sell market order hits the stock exchange, then the sell order gets matched on the best possible available bid orders from buyers who placed their order as a limit order on the bid side.

It is like buying on Amazon. Amazon is the seller and defines the ask. If the price doesn’t matter to you, you place the market order for your favorite product and buy for the best possible price. If you are price-sensitive, you may wait until Amazon’s “ask price” goes lower.

For the seller side, you can take eBay. You see, a seller offers, and he defines the asking price. Buy you are not happy with that price, and you use the option to offer him to buy the product for your favorite price defining your bid price. The seller then has the chance to accept your offer. If he does, then his ask hits your bid.

Trading Volume and Slippage

The higher the trading volume (number of traded shares), the lower the spread between the bid and ask and the lower the slippage when using market orders. The price of a stock does not have anything to do with the bid-ask spread. A high volume stock like AAPL can have a much smaller bid-ask spread than a penny stock. That’s because of the trading volume.

Therefore, spread heavy stocks should be considered to be traded with limit orders, while high-volume stocks can be ordered with market orders. A relative volume indicator can help to identify stocks with a high relative volume in comparison to the typical trading volume per day.

Bid Ask Spread – My Conclusion

Traders would watch the bid price, ask price and bid ask spread closely before placing an order. The market maker executes the trades based on the existing bid and ask prices in the order book. The buyer defines what he is willing to pay per share and defines the stock price limit. The seller defines his price for what he is willing to sell his shares for. The spread is the difference between bid and ask.

We all want to buy for the lowest price possible and sell for a particular stock for the highest price. In investing, the bid ask spread is not that important. Day traders will only make money when taking the bid ask spread into consideration.

Alexander Voigt, CEO
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Alexander Voigt is the founder of DayTradingZ, was a regular contributor to Benzinga and has been featured and quoted on leading financial websites such as,, Business Insider and Forbes.