2. Understand What the Displayed Price Represents

A platform may display a last-traded price, an indicative market value or an executable quote.

These figures serve different purposes.

Prices to Distinguish

• Most recent transaction price.
• Best available bid.
• Best available ask.
• Midpoint between the bid and ask.
• Estimated average execution price.
• Provider’s quoted purchase or sale price.
• Portfolio valuation price.

A last-traded price records a completed transaction. It does not promise that another transaction can occur at the same price or for the same quantity.

Check what the platform’s displayed figure means before using it to estimate transaction proceeds.

3. Review the Bid–Ask Spread

The spread shows the gap between the best available buying and selling prices.

Where liquidity is limited, the gap may be wider, increasing the difference between an immediate purchase price and an immediate sale price.

Hypothetical Example

The spread as a percentage of the midpoint is:

A$0.40 ÷ A$9.80 × 100 ≈ 4.08%.

Buying at A$10.00 and immediately selling at A$9.60 would produce a loss of A$0.40 per unit before fees, assuming sufficient quantities remain available.

The spread is separate from an explicitly charged trading fee.

4. Compare Order Size With Market Depth

The quantity available at the best price may cover only a small part of an intended transaction.

A larger order may need to match additional orders at less favourable prices.

Details to Review

• Quantity available at the best bid or ask.
• Quantities at subsequent price levels.
• Gaps between price levels.
• Total value of the proposed order.
• Estimated average execution price.
• Whether the order preview covers the full quantity.

An order that appears modest in dollar terms can still be large relative to the liquidity available in a particular market.

Order-book information can also change before an order reaches the matching system.

5. Understand How Market Orders Use Available Prices

A market order generally seeks execution against available opposing orders.

It prioritises obtaining execution over specifying a fixed purchase or sale price, subject to the venue’s rules and protections.

Coinbase’s trading rules explain that market orders can execute at multiple prices depending on the quantities available in the order book. Execution may differ substantially from the most recent trade price. coinbase.com

Important Considerations

• The best price may cover only part of the order.
• The average execution price may differ from the initial quote.
• Prices may change during submission.
• Platform protections may restrict execution.
• Some orders may be partly filled or cancelled.
• Fees remain additional unless already included in the quote.

Do not interpret “market order” as a guarantee of a particular price or complete execution.

6. Work Through a Thin Order-Book Example

Consider a hypothetical market purchase of 100 units.

Assume the following sell orders remain available and execute exactly as shown.

Hypothetical Available Sell Orders

Average execution price:

A$1,036 ÷ 100 = A$10.36 per unit.

Difference from the initial best ask:

(A$10.36 − A$10.00) ÷ A$10.00 × 100 = 3.6%.

What the Example Shows

• Only 20 units were available at A$10.00.
• The remaining quantity executed at higher prices.
• The average purchase price was A$10.36.
• The purchase cost exceeded an estimate based entirely on A$10.00.
• Trading fees were not included in the calculation.

This is an illustrative order-book calculation. Actual quantities and prices can change during execution.

7. Understand What a Limit Order Controls

A buy limit order sets the highest price the investor permits for execution. A sell limit order sets the lowest permitted price.

A limit controls the execution price boundary, but it does not guarantee that the order will fill.

Hypothetical Example

An investor places a buy limit order for 100 units at A$10.00.

• Only 20 units are available at or below the limit.
• Those 20 units may execute.
• The remaining 80 units may stay open or be cancelled, depending on the order instructions.
• The investor may not obtain the full intended holding.

The execution-price limit also does not necessarily include separately charged fees. Check the platform’s treatment.

8. Check Partial Fills and Order Duration

Limited matching interest can leave an order partly completed.

The treatment of the remaining quantity depends on the platform and selected instructions.

Order Instructions to Understand

• Good until cancelled: An order can remain open until filled, cancelled or otherwise removed under platform rules.
• Immediate or cancel: Any available portion executes immediately, with the remainder cancelled.
• Fill or kill: The order must execute completely immediately or be cancelled, where supported.
• Expiry instructions: An unfilled order ends at a specified time or date.

Availability and implementation vary between providers.

Review completed quantities before submitting another order. Otherwise, an investor could unintentionally duplicate the unfilled portion while the original order remains active.

9. Distinguish Slippage From Fees and Spreads

Several effects can contribute to the difference between an expected transaction value and the final outcome.

Coinbase describes slippage as the difference between the expected price and the execution price, with available liquidity influencing the result. Coinbase Help

Costs and Effects to Separate

• Bid–ask spread.
• Execution across multiple price levels.
• Price changes during submission.
• Trading fees.
• Provider markups.
• Currency conversion charges.
• Network or withdrawal fees, where applicable.

Use a clearly defined reference when calculating slippage. Comparing execution with the last trade, best ask or order-preview estimate can produce different figures.

Avoid counting a cost twice if it is already reflected in an all-inclusive quote.

10. Check the Specific Trading Pair and Execution Venue

An asset can trade across several venues and quote currencies.

Liquidity available for one pair does not automatically transfer to another.

Items to Review

• Exact trading pair.
• Execution venue.
• Quote currency.
• Relevant order-book depth.
• Pair-specific volume.
• Currency conversion requirements.
• Minimum order size.
• Applicable charges.
• Withdrawal availability.

For example, an asset’s large global trading volume does not establish that its AUD pair has equivalent depth.

Comparisons should consider the complete transaction, including conversion and transfer costs where relevant.

11. Understand the Limits of Splitting Orders

Dividing a transaction into smaller orders can change how it interacts with available liquidity.

However, it does not guarantee a lower total cost.

Factors to Consider

• Whether liquidity replenishes between orders.
• Price changes while the transaction is incomplete.
• Fees applying to each execution.
• Minimum order requirements.
• Time needed to monitor orders.
• Risk of incomplete execution.
• Whether repeated orders continue consuming the same thin liquidity.

A series of smaller purchases can still move through higher price levels.

Assess the complete execution result rather than assuming that smaller individual orders are automatically cheaper.

12. Retain Execution Records and Review the Outcome

The final transaction record provides more useful evidence than the opening price alone.

Keep sufficient information to understand what executed and what remains outstanding.

Execution Details to Record

• Trading pair.
• Order type.
• Order submission time.
• Limit price, where applicable.
• Requested quantity.
• Executed quantity.
• Individual fill prices.
• Average execution price.
• Fees and their currency.
• Remaining open quantity.
• Cancellation status.
• Total amount paid or received.

Use consistent currencies and timestamps when comparing the preview with the completed transaction.

A trade execution record is different from a blockchain transfer confirmation. A later withdrawal may involve separate processing and network fees.

A Practical Crypto Order Execution Checklist

Questions OptimCoins Users Should Ask

People using or considering OptimCoins Australia should confirm how its current service handles purchases and sales.

A provider may use exchange orders, quoted prices or another execution arrangement. Do not assume that every service offers direct access to an order book.

Useful Questions Include

• How are purchases and sales executed?
• Does the displayed price apply to the full transaction?
• Is the quote indicative or executable?
• Which fees or markups are included?
• Can the execution price change after confirmation?
• Are limit orders available?
• How are partial fills handled?
• What happens when liquidity is insufficient?
• Are any price protections applied?
• How are recurring purchases executed?
• Can completed transaction records be exported?
• What information is available about the average execution price?

Confirm these features using current service information rather than assuming OptimCoins provides a particular order type or protection.