Expectations
Backtest vs Broker Statement Why Different
A backtest tool and a broker statement measure different things. Gaps—small or large—are common. Here is why they happen and what to check.
Published: December 26, 2025 · Updated: December 26, 2025 · By FinToolSuite Editorial
Disclaimer
- Educational purposes only, not financial advice.
- Tool outputs are illustrative and depend on inputs and available data.
- Past performance is not a reliable indicator of future results.
- Market returns can be negative.
- See the Privacy Policy for data handling details.
Open the Investment History Checker
Run your dates, then use this guide to understand differences before comparing to a broker statement.
Quick answer
- Brokers record your actual trades and cash flows.
- Tools often use simplified assumptions and end-of-day prices.
- Dividends, fees, taxes, FX, and corporate actions can create differences.
The biggest reasons results differ
Dividends and distributions
Broker statements include cash payouts you received; a price-only backtest may not. See dividends not included.
Fees and taxes
Account fees, commissions, and taxes reduce what you keep. Many tools exclude them. See fees and taxes not included.
Intraday execution and spreads
Brokers record the price you got at a moment in time. Backtests often use end-of-day closes and ignore bid-ask spreads.
Data timing and vendor differences
Vendors can apply corrections on different days. Small timing changes can shift start or end prices, especially on long windows.
Corporate actions and adjustments
Splits, mergers, spin offs, and symbol changes alter price history. Backtests rely on adjusted series. See corporate actions limitations.
Currency conversion and FX rates
Broker statements may show home-currency totals. Backtests often leave returns in the listing currency with no FX conversion unless stated.
Rounding and partial years
Rounding differences and partial first or last years can shift headline percentages. Check your exact start and end dates.
Source of difference and what to check
| Source of difference | What to check | Why it matters |
|---|---|---|
| Dividends | If payouts are included or excluded | Cash returns can lift totals |
| Fees and taxes | Account charges, commissions, withholding | Reduce net performance |
| Execution vs end-of-day price | Your trade time vs the close used | Intraday swings change outcomes |
| Corporate actions | Splits, spin offs, symbol changes | Adjustments shift price history |
| FX and currency | Listing currency vs home currency | FX moves change home-currency value |
| Data timing | Vendor corrections and update lag | Small shifts accumulate over time |
| Rounding and partial years | Decimal places and partial first/last year | Affects headline percentages |
Practical verification checklist
- [ ] Confirm ticker and listing match your broker
- [ ] Confirm the same start and end dates
- [ ] Note whether the tool includes dividends
- [ ] Note whether fees and taxes are included
- [ ] Check if corporate actions occurred in the window
- [ ] If comparing currencies, note the FX assumption or lack of conversion
- [ ] Expect small rounding differences
- [ ] If the gap is large, rerun a shorter window around the gap
What the tool is best for
Use the checker to understand the path directionally, compare different time windows, compare tickers under the same assumptions, and export data for your own review. Treat results as illustrations, not a replacement for a broker statement.
Common questions users ask
- Why is my broker value higher? Broker numbers often include dividends or a better execution price than the end-of-day close.
- Why is my broker value lower? Fees, taxes, spreads, or FX costs reduce what you keep compared with a simplified backtest.
- Why is the start price different? Different vendors, adjustment methods, or currencies can change the opening value.
- Why does the tool show different currency? Results usually stay in the listing currency unless a conversion is applied.
- Why do small differences grow over long windows? Tiny gaps in price, FX, or dividends compound over time.
See the Investment History Checker FAQ for more detail.
FAQ preview
- Does the tool include dividends?
- Does it include fees and taxes?
- What prices does it use?
- What if the ticker changed symbol?
- Where can I learn limitations?
Read dividends not included, fees and taxes not included, corporate actions limitations, and the FAQ.
Ready to compare with clearer expectations?
Run the checker, note what is included, and keep broker differences in mind when reviewing the results.