What Is the Bid Price?
Michael Whitman
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Trading since 2017, full-time since 2020
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YouTube creator, 137K subscribers
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Published 2026-09-14
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Updated
Bid price is the highest price a buyer is currently willing to pay for an asset, and therefore the price a seller receives when selling immediately. It sits below the ask price, and the difference between the two is the spread that every round trip pays.
There is no single price for anything that trades. There are two, one for each direction, and the bid is the one that applies when you are the seller.
How it works
Buyers post the prices they are willing to pay and the highest of those is the bid. It is a live, standing offer from a real participant, not an estimate.
Sell at market and you hit the bid. Your order is matched against that standing buyer, which is why a market sell never gets the price you saw quoted in the middle.
The ticker shows the last trade. That trade happened at somebody else’s bid or ask, at a moment that has passed, and it tells you nothing about what is available now.
Size is half the quote
A bid of 100 for 500 shares is a bid for 500 shares. Sell 2,000 and only the first 500 trade at 100; the rest fill against lower bids sitting beneath it.
That stack of resting buyers is the order book, and depth of market is the display of it. The quoted bid is only its top line.
Which is why a quoted spread understates the cost of a large order. The published number describes a trade at the top of the book, and a large order is not that trade.
A worked example
Bid 99.95 for 500. Ask 100.05 for 400. The spread is 0.10 and the midpoint is 100.00.
Sell 500 at market: you receive 99.95, which is 0.05 below the midpoint. That 0.05 is your half of the spread, and it is a cost even though no fee was charged.
Sell 2,000 instead. The first 500 fill at 99.95, and the remainder fill against whatever bids sit below — 99.90, 99.85, lower. Your average price is worse than the quote you were looking at when you decided.
Nothing went wrong in that second case. The quote was accurate for the size it described, and the order was larger than the size it described.
Why the bid sits where it does
Somebody is being paid to stand there. A market maker posts a bid below fair value and an ask above it, and the gap compensates them for holding inventory they did not choose.
Their risk is being right about nothing and wrong about direction. They buy from sellers and sell to buyers, and if the price moves while they hold the position, the spread has to have been wide enough to cover it.
So the bid is further from the midpoint when uncertainty is high. Wider spreads in fast markets are not opportunism; they are the price of standing in front of a move nobody can see the end of.
And the bid disappears entirely when nobody will stand there. That is not a wide spread, it is no market, and it is what a stop order meets in a gap.
The original data
In the quote above, a round trip costs 0.10, one full spread, which is 0.1% of the 100.00 midpoint. No statement lists it, because it is taken in the prices rather than charged as a fee.
Half of that round trip is the bid side. You give up 0.05 selling and the same again buying, and neither appears as a line item on any statement.
At 0.1% a time, one round trip is small and a year of them is not. A strategy trading daily pays that cost around 250 times a year, 25 percentage points of turnover cost if simply added up, which is where an apparently tiny number becomes the difference between a profitable system and a losing one.
What actually moves it
Order flow. A run of market buy orders consumes the resting asks, the book thins on that side, and market makers raise the bid to keep their inventory balanced.
Information. News that changes what the asset is worth moves both sides at once, often with no trade in between — the quote simply reprints somewhere else.
Time of day. Bids are thinnest at the open and in premarket and after-hours sessions, where far fewer participants are posting.
And the size of the thing being quoted. A large, heavily traded instrument carries bids for large size at a narrow distance; a small one carries a thin bid that a single ordinary order can exhaust.
How this connects
A limit order is how a seller declines the bid. Posting an offer instead of hitting the bid saves the half-spread, at the cost of possibly not trading at all.
A stop-limit order sets a floor on the bid it will accept, which protects against selling into an empty book but can leave the position unsold. A plain stop loss has no floor: once triggered it takes whatever bid exists.
Liquidity is, in practice, the size and closeness of the bids. A liquid instrument has many of them stacked tightly beneath the top one.
An iceberg order hides part of its size, so the visible bid can understate how much a buyer is prepared to take at that price.
Payment for order flow changes who fills a retail sale. A wholesaler buys the order and often fills it at or slightly better than the displayed bid.
Time and sales shows which side trades are printing on, so a run of prints at the bid reads as sellers accepting buyers’ prices.
High frequency trading firms post much of the displayed bid in liquid shares, updating it constantly, which keeps quoted spreads narrow and makes the quote quick to vanish.
And a penny stock shows the problem at its worst: a thin bid, for small size, well below the last trade.
When it fails
The characteristic failure is calculating a position’s value at the ticker price. A holder marks their position at the last trade, sees a number, and plans around it — but the last trade was somebody else’s transaction at a price that may no longer be available in any size. The realisable value of a holding is what the bids will actually absorb, and for a thinly traded instrument that can be materially below the displayed price. The statement is not wrong; it is measuring something other than what you can get.
A second failure is ignoring size on the quote. A tight spread for 100 shares says nothing about a 10,000-share order.
A third is assuming the bid is always there. In a gap the book empties, and a market sell fills wherever the next buyer happens to be.
A fourth is treating the spread as a trivial cost because each instance is small. Frequency turns it into the largest cost most active traders pay.
The question: The ticker says 100. What will you get?
And a fifth is comparing a fill to the midpoint and calling the difference slippage. The midpoint was never available to you — you were always going to trade at one side or the other.
Related
Ask price covers the other half of the quote. Bid-ask spread covers the gap between them and what it pays for. And order book covers the stack of bids sitting underneath the top one.
The number on the ticker is where somebody else traded. The bid is where you can trade. Those two are usually close and they are never the same thing, and every cost estimate that starts from the ticker price starts from the wrong number.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.