Have you ever opened a trade and noticed it was already in a small loss the second it began? You didn’t do anything wrong. You just met the bid-ask spread.
The spread is one of the most basic ideas in trading, yet many beginners never truly understand it. Once you do, you’ll see why trades cost money, why prices suddenly “jump” during news, and what traders mean when they talk about crossing the spread.
Let’s unpack it step by step, without jargon.
Every Market Has Two Prices
When you check the price of a stock, a currency pair, or a cryptocurrency, the single number you see is a simplification. In reality, there are always two prices:
- The bid: the highest price a buyer is currently willing to pay.
- The ask (also called the offer): the lowest price a seller is currently willing to accept.
A Simple Everyday Example
Think about a currency exchange booth at an airport. The board might show:
- We buy dollars at 278
- We sell dollars at 284
If you hand them dollars, you get the lower number. If you want to buy dollars from them, you pay the higher number. That gap is how the booth earns its living. Financial markets work exactly the same way, just faster and usually with much smaller gaps.
💡 Tip: Remember it from your side: you sell at the bid and buy at the ask. You always buy at the higher price and sell at the lower one.
What Is the Bid-Ask Spread?
The bid-ask spread is simply the difference between the two prices:
Spread = Ask price − Bid price
If a stock shows a bid of $20.00 and an ask of $20.05, the spread is $0.05.
The price halfway between them is called the mid price (or mid-market price). In our example, that’s $20.025. Many charts display something close to this, which is why the price you see and the price you get can differ slightly.
Measuring the Spread as a Percentage
A five-cent spread means very different things on a $2 stock and a $500 stock. That’s why traders often measure it as a percentage:
Spread % = (Ask − Bid) ÷ Mid price × 100
- $0.05 spread on a $20 stock = about 0.25%
- $0.05 spread on a $500 stock = about 0.01%
The second one is far cheaper to trade.
How Spreads Are Quoted in Different Markets
| Market | How spread is usually shown | Example |
|---|---|---|
| Stocks | Cents | Bid $20.00 / Ask $20.05 |
| Forex | Pips | EUR/USD 1.0850 / 1.0851 = 1 pip |
| Futures | Ticks | One tick wide on liquid contracts |
| Crypto | Price or percentage | Varies widely by coin and exchange |
Why Does the Spread Exist?
The spread isn’t a fee someone randomly invented. It forms naturally because buyers want to pay as little as possible and sellers want to receive as much as possible. Until somebody gives in, there’s a gap.
The Role of Market Makers
Market makers are firms or traders who keep both a bid and an ask in the market at all times. They’re happy to buy from you or sell to you, and they profit by capturing the spread repeatedly, buying slightly lower and selling slightly higher.
In return, they provide a valuable service: liquidity. Without them, you might have to wait a long time to find someone willing to trade with you.
Market makers also take on risk. If price moves sharply against the position they’ve just picked up, they can lose money. That risk is a big reason spreads widen when markets get nervous.
💬 Quote: “Remember that time is money.” — Benjamin Franklin, Advice to a Young Tradesman (1748)
What Makes a Spread Wide or Tight?
| Factor | Tight spread | Wide spread |
|---|---|---|
| Liquidity | Many buyers and sellers | Few participants |
| Trading volume | High | Low |
| Volatility | Calm market | Fast, jumpy market |
| Time of day | Main trading sessions | Overnight, holidays, pre-market |
| News | Normal conditions | Big announcements |
| Asset type | Large stocks, major currency pairs | Small-caps, exotic pairs, minor coins |
Why Spreads Widen During News
Right before a major economic release, market makers pull back their quotes or widen them to protect themselves. Fewer orders sit in the book, so the gap between the best bid and best ask grows. This is why a trade placed seconds before big news can be surprisingly expensive.
💡 Tip: If you trade forex, check the spread at different times of day. Spreads on many pairs are often tightest when major sessions overlap and widest during quiet hours.
What Does “Crossing the Spread” Mean?
Now for the key idea. Crossing the spread means placing an order that trades immediately against the other side of the market.
- A buyer who crosses the spread pays the ask instead of waiting at the bid.
- A seller who crosses the spread accepts the bid instead of waiting at the ask.
In other words, the trader “walks across” the gap to meet the other side. This usually happens with a market order, or a limit order priced at or through the opposite side.
Picture two groups standing on opposite banks of a narrow river. Buyers stand on one bank, sellers on the other. Nobody trades while both sides wait. The moment someone decides they can’t wait any longer, they cross the bridge and accept the other side’s price. That person has crossed the spread.
Crossing Is the Aggressive Act
The trader who crosses the spread is the aggressive side of the trade, also known as the taker. The trader whose resting order gets hit is the passive side, or maker.
This matters because price only moves when someone crosses the spread. If buyers keep crossing and paying the ask until sellers at that level run out, the ask moves higher, and so does the price.
So, Who Crosses the Spread?
Many different people cross the spread, each for their own reasons.
1. Traders Who Need Speed
Anyone who must get in or out right now, such as a trader hitting a stop-loss or chasing a breakout, will usually cross the spread. For them, certainty is worth the extra cost.
2. Most Retail Investors
Everyday investors often use market orders out of habit or convenience. Every one of those orders crosses the spread.
3. Institutions With Urgency
Big funds usually prefer to work their orders patiently. But when news breaks or risk needs to be cut fast, they may cross aggressively, which can cause sharp price moves.
4. Momentum and Breakout Traders
These traders believe a move is starting and don’t want to miss it. Waiting passively at the bid might mean the train leaves without them.
And Who Doesn’t?
Market makers and patient limit order traders generally sit on the passive side. They let others come to them and earn the spread instead of paying it.
💬 Quote: “Buy low, sell high.” — The oldest advice in trading. The spread is the first obstacle between you and following it.
The Real Cost of Crossing the Spread
Each time you cross, you pay roughly the spread. And because most trades have both an entry and an exit, you often pay it twice if you cross on both sides. Traders call this the round-trip cost.
A Simple Example
Suppose a stock is quoted at $50.00 bid / $50.10 ask.
- You buy with a market order at $50.10.
- Instantly, the best you could sell for is $50.00.
- Your trade starts $0.10 per share in the red.
On 500 shares, that’s $50 you need to recover before you make a single cent. This is exactly why new trades often open in a small loss.
For a long-term investor holding for years, this cost hardly matters. For a day trader or scalper making many trades daily, spread costs can quietly eat a large share of profits.
💡 Tip: Before taking a short-term trade, compare your profit target to the spread. If the spread is a big chunk of your target, the trade may not be worth it.
Effective Spread: What You Really Pay
The quoted spread is what you see on screen. The effective spread is what you actually pay after your order fills.
If your order is larger than the size available at the best price, you may get filled at several worse levels. That’s slippage, and it makes your real cost bigger than the quoted spread. On the other hand, some brokers occasionally fill orders slightly inside the spread, which makes your cost smaller.
How to Reduce Spread Costs
You can’t avoid spreads entirely, but you can keep them small:
- Trade liquid assets. Popular stocks, major currency pairs, and large crypto coins usually have tight spreads.
- Trade during active hours. Avoid pre-market, overnight sessions, and holiday periods when liquidity is thin.
- Stay clear of major news moments unless your strategy is built for them.
- Use limit orders when you aren’t in a hurry, so you can join the passive side instead of crossing.
- Compare brokers. Spreads, especially in forex and CFDs, can differ noticeably between providers.
- Trade less often. Fewer round trips mean fewer spreads paid.
💡 Tip: Look at Level 2 quotes or the order book if your platform offers them. Seeing how much size sits at the best bid and ask tells you whether a market order will fill cleanly or slip.
Final Thoughts
The bid-ask spread is the small gap that every trade has to cross. Buyers bid, sellers ask, and the spread sits between them. Crossing the spread means choosing speed over price, accepting the other side’s terms to get your trade done right away.
Patient traders and market makers wait and earn the spread. Urgent traders cross it and pay. Neither choice is wrong, but knowing which side you’re on, and what it costs you, is one of the simplest ways to become a smarter, more cost-aware trader.
I’m Abdullah Shah, a content writer with three years of experience in crafting engaging and informative content. My background in market analysis complements my work, allowing me to create content that resonates with audiences. I’m also a seasoned practitioner in the forex and crypto markets, with a strong foundation and deep interest in finance. My passion for the financial world drives me to produce content that is both insightful and valuable for those interested in understanding market trends and financial strategies.
