Why you should know this
Without a benchmark and record, traders cannot tell whether results came from market direction, execution skill, fees or luck.
This is not about being told which trade to take. We are learning how to inspect the mechanism together, so a later decision is more deliberate and reviewable.
The short answer
This lesson introduces implementation shortfall, effective spread, fill rate and benchmark comparison.
Average fill price
The prices, quantities and fees in the worked examples below are illustrative teaching inputs. They are not market observations, market averages or a DOPAY/provider execution record; their purpose is to make each formula reproducible.
For multiple fills:
Average fill = Sum of price × quantity ÷ Total filled quantity
Example buy:
- 200 units at ₱100;
- 300 at ₱101;
- 500 at ₱102.
[(200 × 100) + (300 × 101) + (500 × 102)] ÷ 1,000 = ₱101.30
Do not use the simple average of 100, 101 and 102; quantities differ.
Fill rate
Fill rate = Filled quantity ÷ Intended quantity × 100
If 1,000 of an intended 1,500 units execute:
1,000 ÷ 1,500 × 100 = 66.67%
A high fill rate is useful when completion matters. It can be poor if achieved at an unacceptable price. A low fill rate can be prudent if a limit protected the boundary.
Effective spread
Effective spread compares execution with the midpoint near execution. A common form is:
Effective spread = 2 × Direction × (Fill price − Midpoint)
Use Direction = +1 for buys and −1 for sells so a positive result represents cost.
If midpoint is ₱99.50 and buy fill is ₱100:
2 × 1 × (100 − 99.50) = ₱1.00
As a percentage of midpoint:
₱1 ÷ ₱99.50 × 100 ≈ 1.01%
This estimates the round-trip spread implied by the execution relative to midpoint. It is not the same as total cost.
Implementation shortfall
Implementation shortfall compares the paper portfolio implied by the decision price with what was actually executed, including unexecuted quantity under a defined valuation.
A simplified buy example:
- intended: 1,500 units;
- decision price: ₱100;
- filled: 1,000 at ₱101.30;
- 500 unfilled, later valued at ₱103;
- explicit fee: ₱300.
Execution cost on fills:
(₱101.30 − ₱100) × 1,000 = ₱1,300
Opportunity cost on unfilled quantity:
(₱103 − ₱100) × 500 = ₱1,500
Simplified shortfall:
₱1,300 + ₱1,500 + ₱300 = ₱3,100
As a percentage of intended decision value of ₱150,000:
₱3,100 ÷ ₱150,000 × 100 ≈ 2.07%
The valuation time for the unfilled amount must be defined. Different choices answer different questions.
Data-quality cautions
Exchange timestamps may use different clocks. Screenshots can omit updates. Order books change between capture and arrival. Unfilled orders need a defined opportunity-cost valuation.
Preserve raw reports where possible and state every assumption. Precision in a spreadsheet cannot repair a weak benchmark.
A familiar Philippine or Asian example
A learner in the Philippines studies a fictional crypto quote and writes the pair direction, intended action, price control, estimated cost, possible fill problem and exit plan. The exercise uses paper values only. No order is placed.
One risk or limitation
Examples simplify execution. Real venues differ in order logic, trigger source, fees, tick and lot sizes, available liquidity and outage handling. A checklist can reduce avoidable mistakes, but it cannot guarantee a price, fill, exit or profit.
How this connects to market mastery
Market mastery includes execution discipline. A strong market view can still fail when the pair, order type, size, liquidity, fee or exit mechanics are misunderstood.
Quick check — no money needed
Use a fictional quote. Write the pair, buy or sell action, order type, price control, size, estimated fees, liquidity concern and the condition that would cancel the plan. Then explain which field protects you from the largest avoidable mistake.
If you can explain your answer and name the main limitation, this lesson is complete.
*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.
