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A chart can display a last-traded, midpoint or other reference price while an order uses a different quote. Identify the price type before treating a visible line as an executable level.
Define the three terms
Bid is a quoted buying price and ask a quoted selling price in the relevant market or feed. Last price records a transaction price. The spread is ask minus bid at the same observation time.
A last transaction can be older than the current quotes. A midpoint is a calculation, not proof that an order can trade there. The feed and product determine which values are available.
An original snapshot
Suppose the bid is 99.90, ask is 100.10 and last transaction was 100.00. The spread is 0.20 and midpoint is 100.00.
If an illustrative market purchase executes at the ask and an immediate sale at the bid, the difference is 0.20 before other costs. That example does not establish a rule for every binary contract, whose reference and payoff must be checked separately.
Read the chart and order specification together
| Item | Question |
|---|---|
| Chart series | Last, bid, ask, midpoint or provider reference? |
| Order quote | Which side or reference is accepted? |
| Timestamp | Are both values from the same instant? |
| Settlement | Which defined quote decides the result? |
Do not transfer one platform’s convention to another
TradingView’s help gives examples of chart and execution differences in particular connections. Those explanations illustrate the need to inspect the actual quote basis; they are not a universal statement about every symbol or broker.
If a fixed-outcome provider uses a specified server quote, investigate that reference directly rather than assuming it equals an outside chart’s last price.
Compare like with like
Capture full instrument names, feeds, price types, precision and timestamps. A small mismatch can result from different sources or timing, but a possible explanation is not proof of the cause.
Ask for the accepted record if investigating an order. Preserve an outside chart as supporting context while keeping its limitations visible.
What accurate terminology improves
It makes fee comparisons, chart audits and dispute descriptions more precise. It does not establish that an apparent price difference is harmless or malicious without further evidence.
A useful conclusion identifies exactly which two prices differed and what remains unknown. Avoid claiming there is one universally correct visible price for every type of market and contract.
Read quotes from the trader’s perspective
For an ordinary quoted two-sided market, the bid is the price a buyer quotes and the ask is the price a seller quotes. A trader buying at the displayed ask and selling at the displayed bid crosses the spread. Actual order execution still depends on order type, available liquidity, size and the platform’s execution rules.
Do not assume the best displayed quote guarantees execution for every order quantity. Also avoid applying this trading convention automatically to a fixed-outcome contract. That contract may use a defined reference price and payout condition rather than a buy-and-sell transaction in the underlying instrument.
Bid, ask, midpoint and last: one fictional snapshot
| Price measure | Illustrative value | Meaning |
|---|---|---|
| Bid | 99.90 | Current quoted buying side |
| Ask | 100.10 | Current quoted selling side |
| Midpoint | 100.00 | Arithmetic average of those two quotes |
| Last | 99.95 | Price of a recorded transaction, potentially from an earlier moment |
This is a second invented snapshot; it deliberately uses a last price different from the midpoint. The earlier example happened to make them equal. Neither equality nor difference establishes a pricing error without the actual feed and timestamp.
The spread here is 0.20. Expressed relative to the 100.00 midpoint, it is 0.20%. If a fictional position represented ten units and could be bought at 100.10 then immediately sold at 99.90 without quote changes, the price difference would be two account-value units before other costs. This is arithmetic, not a specification for any broker’s contract.
Official platform examples have a defined scope
TradingView’s cited support article describes a situation where a midpoint chart is compared with bid/ask execution, including the opposite side used when closing a position. It explains that particular chart-versus-order difference; it should not be treated as proof that all TradingView symbols use midpoint candles.
MetaTrader 5 documentation separately describes quote fields in Market Watch and the chart option for displaying an ask line. Its chart guidance explains why the side relevant to a position can differ from the visible bid line. Check the actual symbol, chart mode and broker configuration before applying a remembered convention.
Build a useful price-comparison record
- Keep the complete symbol, including suffixes and any special market label.
- Identify the feed or venue and whether the displayed series is bid, ask, last, midpoint or another reference.
- Record timestamps with timezone and sufficient precision for the question being investigated.
- Preserve the submitted order settings and accepted execution record separately.
- For an expiry-based product, retain the specified settlement source and outcome rule.
- List unresolved differences rather than declaring a cause from one screenshot.
Two screenshots taken a second apart may show different market states. A candle high or low summarises an interval and is not a complete quote-by-quote execution record. A price at which a chart traded does not by itself establish that the required opposite-side quote was available for your order.
Do not confuse spread, commission and slippage
Spread describes the contemporaneous gap between quoted sides. Commission is a separately specified charge where applicable. Slippage describes a difference between an expected or requested reference and actual execution under a defined comparison. Keep those fields separate when attributing an apparent cost.
A changed execution price is not automatically explained by spread; timestamps or market movement may also matter. Conversely, an expected spread difference is not proof that every disputed fill was correct. Ask for the relevant transaction evidence and execution terms.
Frequently asked questions
Can a midpoint always be traded?
No. It is a calculated reference. Whether any order can execute there depends on the market, order and available counterparties.
Is last price the latest bid or ask?
No. Last refers to a transaction price. Its age and source need checking separately from current quotes.
Does an outside chart decide a binary contract’s outcome?
Not automatically. Read the contract’s defined reference and settlement rules. An external chart can provide context without being the agreed settlement source.
Does a small mismatch prove manipulation?
No. Establish the two values, timing and sources first. It also should not be dismissed without evidence. Our market-data academy and research methodology explain how to describe a limited finding.
Sources and research scope
- TradingView chart information: bid and ask
- TradingView execution-price versus chart-close explanation
- MetaTrader 5: Market Watch quote fields
- MetaTrader 5: chart settings and ask line
Public-source review: 25 October 2026. Examples are illustrative. Documentary research does not represent funded-account testing. Rules must be checked against the current product, entity and customer location.
Related research
Market data academy · Research methodology · Calculation tools
Risk: Fixed-outcome contracts can lose the entire stake. No chart pattern, calculator or demo result guarantees future returns.