Worked example: negative swap in a number-based scenario
Negative swap refers to a situation where the overnight financing component (“swap” or “rollover”) for a held position results in a credit to the account rather than a charge. A “worked example” makes this concrete by showing the sign (credit vs. debit) and the arithmetic—while clearly listing every assumption.
How negative swap works (mechanism and inputs)
In many forex account setups, swap is calculated when a position is held past a rollover point (often described as an “overnight” or “daily” processing time). The direction and magnitude depend on the interest-rate relationship between the two currencies in the pair and on how your provider applies swap/financing rules.
To keep the example self-contained, use these generic inputs:
- Pair: choose one instrument (we will not use live quotes).
- Position size: expressed in lots (or units), since swap is typically calculated per lot.
- Swap rate: an overnight financing value per lot for the direction you hold (long vs. short). We will treat this as an assumed number.
- Number of rollovers: how many overnight events your position remains open.
Worked numerical example (explicit assumptions)
Below is a scenario that illustrates the sign and calculation only. It is not a prediction.
Assumptions
- You hold a single position of 1.00 lot in a forex pair overnight.
- Your provider applies an assumed swap credit for this direction of +3.50 currency units per lot per rollover.
- The position experiences 1 rollover (one overnight processing event) during the time window you care about.
- Ignore any other account items (commissions, fees, spreads) so the arithmetic isolates swap.
- Ignore currency conversion differences for presentation: treat the swap credit as already expressed in your account’s base currency for simplicity.
Calculation
- Swap result for 1 rollover = position lot size × swap credit per lot
- = 1.00 × 3.50
- = +3.50 (a credit)
Interpretation
If the swap were negative in the same scenario (for example, an assumed −3.50 per lot instead of +3.50), the account would be debited instead. Negative swap is about the direction of the overnight financing cashflow under your provider’s rules for that instrument and position direction.
Limitations and failure modes (what can change)
- Provider-specific swap rules: The swap rate used in the example is an assumption. In reality, providers publish their own swap/rollover calculations, and the value can differ by account type and contract terms.
- Market-condition dependence: The underlying interest-rate relationship can change over time, which means the overnight financing terms can change even if the trade direction stays the same.
- Rollover timing effects: If your position spans different rollover dates or processing times, you may experience more than one rollover event, changing the total.
- Other costs are separate from swap: Even if swap is credited, the position can still incur costs through spread widening, execution impacts, or other fees not included in the worked arithmetic.
Verification and a next question to check independently
To verify a negative swap claim for your own situation, you can independently map the example’s assumptions to your provider’s published swap/overnight financing rules:
- confirm the swap credit/debit sign for your pair and whether you are long or short;
- confirm the per-lot swap amount and how it is computed;
- confirm the number of rollovers that apply to the period you plan to hold.
A useful next question is: What swap/rollover value (per lot) and sign does your provider state for your instrument and position direction, and what rollover dates/times affect your planned holding window?