A strategy that trades frequently can look profitable before costs and unprofitable after them. Costs are not a footnote; for short-term strategies they are often the single largest factor in the result.
What to include
- Commissions — even “zero-commission” brokers have regulatory fees.
- Bid-ask spread — you usually buy at the ask and sell at the bid.
- Slippage — market orders in fast markets fill worse than the last price.
- Borrow fees — short positions on hard-to-borrow stocks can be expensive.
We recommend testing every strategy at several cost levels so you can see how sensitive it is.
Important: Backtested results are hypothetical and are prepared with the benefit of hindsight. They do not represent actual trading and do not guarantee future performance. DataBacktest does not provide investment advice. See our Risk Disclaimer.
Let’s talk
Have a dataset or a strategy you want tested properly?
Tell us what you’re working on. Mark or a member of the team will reply within one business day with a scope and a fixed quote.