Trading costs and slippage in backtests: a FiClaw net-return review guide
Review commissions, slippage, turnover and fill assumptions, then compare cost scenarios with fixed strategy settings and traceable FiClaw research evidence.
Published by FiClaw 产品团队 · Published · Updated
阅读中文版Quick answer
Assess net returns by documenting how fees and slippage affect fills and cash, then comparing cost scenarios with the strategy, data and period held fixed. Frequent turnover makes buy-side and sell-side costs, execution limits and sensitivity especially relevant. FiClaw can assist with backtests and comparisons; verify the actual fee and matching models.
For researchers examining frequently rebalanced strategies or explaining the difference between gross and net results.
Example sensitivity request: change only the cost assumptions
Keep the specification, code, universe, data dates and parameters fixed. Document units and treatment of fees, applicable taxes, slippage and fill constraints. After confirmation, compare baseline, higher-fee and higher-slippage scenarios. Record net return, drawdown, turnover, trades, unfilled orders and accumulated costs. Keep parameter search separate and mark unsupported modeling assumptions.
Distinguish fees, slippage and execution constraints
Document fee direction, units, minimum charges and the historical period covered. Applicable charges depend on the market and account; verify the relevant rules instead of treating one number as the complete cost model.
Slippage is a difference between a reference price and the simulated fill. Direction, timing and quantity can matter. Suspensions, price limits and volume constraints can prevent execution altogether, which a fixed cost deduction cannot fully represent.
Hold the experiment fixed before changing costs
Save a complete baseline, then vary fees or slippage separately. Compare net return, drawdown, trade count and unfilled orders. Distinguish one-way from round-trip charges and percentage from quantity-based costs to avoid omissions and double counting.
Costs can change available cash and later positions. Subtracting an aggregate charge from a completed gross-return curve is therefore not always equivalent to rerunning the strategy. Check when the engine applies fees, prices and cash constraints.
Keep the assumptions behind a FiClaw comparison
Include costs and matching assumptions in the specification and runtime configuration. Inspect generated code for units, trade direction and cash treatment. FiClaw can organize backtests and diagnosis; confirm available settings and evidence against the current backtest interface.
Report dependence on optimistic cost assumptions before deciding whether to continue research. A simplified simulated fill model does not establish live capacity, and its results do not replace independent review.
Compare costs with a consistent experiment record
| Comparison | What to retain | Review focus |
|---|---|---|
| Baseline | Strategy, data, dates, parameters and costs | Can the experiment be reproduced? |
| Fee change | Direction, units, minimum charges and total fees | Were charges applied during execution? |
| Slippage change | Price direction, execution time and fill limits | Are assumed prices and quantities feasible? |
| Result change | Net return, drawdown, turnover, trades and unfilled orders | Does the conclusion depend on optimistic assumptions? |
Frequently asked questions
Are transaction costs and slippage the same?
No. Explicit charges follow the relevant market and account rules; slippage describes a difference between reference and fill prices. Both affect results, while execution constraints can also prevent fills.
Is a fixed basis-point slippage assumption enough?
It can be a clearly labeled simplified scenario, but it does not establish live capacity or fill quality. Review liquidity, order size, matching rules and unfilled-order handling as well.
Are FiClaw example reports actual execution results?
No. Examples illustrate research and report structure. Actual results depend on data, strategy, costs and matching settings; example metrics are not user results or live returns.
Method references
- Backtrader: Commission Schemes
Technical background, not a claim that FiClaw uses this engine or its defaults.
- Backtrader: Broker Slippage
Explains interactions between slippage and matching rules; confirm FiClaw's rules separately.
Related resources
- Cost-sensitivity report example →
- Backtest report review checklist →
- Out-of-sample and walk-forward validation →