Why you should know this
A screen may show one large price, a green buy button, a red sell button and a moving chart. It can feel as though the asset has one exact price. In an order-book market, several prices coexist.
Knowing the difference protects us from a classic surprise: seeing a last price of ₱100, buying, and receiving an average fill above ₱100. This lesson also prepares us to understand market orders, limit orders, liquidity, maker/taker fees and slippage.
The four values
Bid
The best bid is normally the highest displayed price at which a buyer is currently willing to buy the base asset.
If the best bid is ₱99.50, a marketable seller may be able to sell some quantity at ₱99.50—subject to the displayed size still being available.
Ask
The best ask, sometimes called the offer, is normally the lowest displayed price at which a seller is currently willing to sell the base asset.
If the best ask is ₱100.50, a marketable buyer may be able to buy some quantity at ₱100.50—again subject to available size.
Spread
The bid-ask spread is the gap between the best ask and best bid:
Spread = Best ask − Best bid
With a ₱99.50 bid and ₱100.50 ask:
₱100.50 − ₱99.50 = ₱1.00
The spread is a visible trading cost for someone who immediately buys at the ask and sells at the bid, even before explicit fees.
Last price
The last price is the price of the most recently reported trade on that venue. It tells us where a transaction happened, not what the next transaction is guaranteed to receive.
The last trade could be seconds old, unusually small or on the opposite side of the current quote. In a fast market, the order book can move before a human reads the number.
Who looks at which side?
If we want to buy immediately, the ask side matters first because that is where sellers are offering inventory.
If we want to sell immediately, the bid side matters first because that is where buyers are bidding.
The last price is useful context, but it is neither a standing buy promise nor a standing sell promise.
An easy memory aid:
- buyers ask what sellers will accept;
- sellers check what buyers bid.
Midpoint and percentage spread
Analysts sometimes calculate the midpoint:
Midpoint = (Best bid + Best ask) ÷ 2
Using ₱99.50 and ₱100.50:
(₱99.50 + ₱100.50) ÷ 2 = ₱100.00
The quoted percentage spread can be estimated as:
(Ask − Bid) ÷ Midpoint × 100
₱1.00 ÷ ₱100.00 × 100 = 1%
This helps compare a ₱1 spread on a ₱100 asset with a ₱1 spread on a ₱10,000 asset. The absolute gap is the same; the relative cost is not.
The round-trip lesson
Suppose Ana buys one unit at the ₱100.50 ask and immediately sells at the unchanged ₱99.50 bid. Her price loss is ₱1 before fees:
₱99.50 − ₱100.50 = −₱1.00
The market price did not need to “fall” for her to lose. She crossed the spread twice.
This is why very frequent trading can accumulate costs even when the trader’s directional ideas are roughly correct.
Displayed size matters
A best ask of ₱100.50 might have only two units available. A buy order for ten units could consume:
- 2 units at ₱100.50;
- 3 units at ₱101.00;
- 5 units at ₱102.00.
The average fill would be:
[(2 × 100.50) + (3 × 101.00) + (5 × 102.00)] ÷ 10 = ₱101.40
The best ask was real for the visible two units, not for the entire ten-unit order. Market depth and slippage explain the rest.
Why spreads widen
Spreads can widen when:
- price is moving quickly;
- few participants are quoting;
- the asset or pair is thinly traded;
- news creates uncertainty;
- market makers face higher inventory or hedging risk;
- a venue has operational trouble;
- local funding or Withdrawal access is strained.
A wide spread is information. It may signal that immediacy is expensive or that the market cannot absorb much size. It does not identify the exact cause by itself.
Last price can mislead without being false
Imagine the last trade was ₱100. Then sellers cancel their offers and the new best ask becomes ₱105. The screen may briefly emphasize ₱100 while the immediate buyable price is ₱105.
Or a tiny trade at ₱105 may set the last price while the midpoint remains around ₱100. A single print can look dramatic without representing the price available for meaningful size.
Check timestamp, bid, ask and depth rather than accusing the data of being wrong.
Order-book venue versus broker quote
Not every interface exposes a public order book. A broker or conversion service may show one executable quote that already incorporates spread, fee or risk controls. The user may not see separate bid and ask queues.
The economic questions remain:
- How much will I give?
- How much will I receive?
- For how long is the quote valid?
- Which fees are separate?
- Can the final amount change before confirmation?
Do not assume an order-book definition describes every provider’s model.
Philippine and Asian context
The same crypto asset may have a narrow USDT spread on a large global venue and a wider PHP spread on a smaller local market. That does not automatically mean the local quote is unfair. Liquidity, banking rails, market hours, risk, fees and participant mix differ.
For a user who ultimately needs PHP, the global dollar price is only a reference. The usable result depends on the executable local quote and complete conversion path.
The QUOTE check
Before entering an order:
- Q — Quantity: how much is available at the best level?
- U — Updated: when did the data last change?
- O — Order side: am I buying at asks or selling into bids?
- T — Total cost: spread, fees and likely slippage?
- E — Executable: is this a firm quote, visible order or historical trade?
This takes seconds once it becomes a habit.
Common mistakes
- Calling the last price “the buy price.”
- Looking at the bid when preparing an immediate buy.
- Comparing absolute spreads across very different price levels.
- Ignoring the quantity available at the top of book.
- Treating displayed liquidity as guaranteed.
- Assuming the same pair has the same spread on every venue.
- Forgetting that broker quotes and order books work differently.
A no-money quote drill
Create a fictional quote:
- Bid: ₱57.90 for 200 units
- Ask: ₱58.10 for 50 units
- Last: ₱58.00
Now answer:
- What might an immediate buyer pay for up to 50 units?
- What might an immediate seller receive for up to 200 units?
- What is the absolute spread?
- What is the approximate percentage spread?
- What information is missing for an order of 500 units?
No funds are needed to practise quote literacy.
How this connects to market mastery
Bid, ask, spread and last price form the first layer of execution analysis. Later, we will compare intended price with average fill, effective spread and implementation shortfall.
The advanced formulas are extensions of today’s basic question: what price was actually available for our side and our size?
Key takeaways and check
- Bid is the strongest displayed buy interest; ask is the lowest displayed sell interest.
- Spread is ask minus bid.
- Last price is a historical execution, not a promise.
- Size at each level determines whether the top quote covers the whole order.
- For Philippine users, local executable value matters more than a distant reference alone.
Market Explorer check: With a ₱199 bid, ₱201 ask and ₱200 last price, label all four values and calculate the midpoint and percentage spread.
*Cryptocurrency and virtual asset transactions are highly volatile and irreversible, may result in significant losses, and do not guarantee returns; customers should trade only after understanding the risks involved.
