Trade profits are determined not by “signals” but by “structure”
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― Redefinition of Execution Design
Many trading strategies focus on the signal design of “when to enter.”
However, in actual operation, profits are not determined by that signal.
Profit is determined by the “structure.”
Here, the structure refers to the integration of the following elements.
- Execution (order method)
- Costs (spread, slippage, fees)
- Liquidity (depth, market impact)
- Inventory risk (position management)
The signal is only a part of it.
Why signal-centric design collapses
Strategies that show an edge in backtests often fail in real operation.
The main cause is clear.
- Spreads are wider than expected
- Frequent slippage
- Orders do not fill / partial fills occur
- Prices move the moment you hit the book
In other words,
the strategy assumes orders will be filled.
At this point, the strategy is unfinished.
Redesign around Execution
Execution design is not simply choosing market order or limit order.
It is the process of adapting the strategy’s expected value to actual market conditions.
1. Endogenize the spread
- Incorporate “minimum spread” into entry conditions
- Prohibit entries in spread-widening environments
→ Reduce unnecessary trades
2. Convert slippage to a probability distribution
- Treat as a distribution rather than a fixed value
- Vary with volatility and depth
→ Narrow the gap between backtests and real trading
3. Optimize order execution strategy
- Market order: prioritize certainty
- Limit order: prioritize cost
- Split orders: reduce market impact
→ Select the optimal Execution for each strategy
4. Liquidity-based filtering
- Incorporate depth as a condition
- Avoid trades when liquidity is insufficient
→ Avoid participating in adverse markets
Trade design as a structure
When integrated, trading can be decomposed as follows.
- Signal: directional hypothesis
- Execution: how to implement that hypothesis
- Cost: frictions associated with execution
- Liquidity: constraints on feasibility
Many strategies design only the “Signal.”
However, actual profits are
diminished by Execution × Cost × Liquidity.
Strategies that ignore this attenuation do not structurally hold up.
Implementation in Practice
What matters in real trading is not a highly accurate signal, but the following:
- Trading at prices where orders can be filled
- Expectation is positive when including costs
- Not having overly large sizes relative to liquidity
For example,
- VWAP-based execution
- Price adjustment based on the best bid and offer (BBO)
- Spread adjustments according to inventory risk
All of these are designed centered on Execution.
Conclusion
Trading strategies are not a guessing game.
They are a game of designing executable structures.
- Signals are important, but not sufficient on their own
- A strategy that does not design Execution collapses in real markets
- Profit is determined not by logic but by the completeness of the structure
What will be required going forward is
not competition of signal accuracy but optimization of structural design.