Direct answer
Rollover for USD/CHF (often called “swap” in forex platforms) is the interest adjustment applied when a position is held from one roll date to the next. Conceptually, it comes from the interest-rate difference between the two currencies, converted into a per-trade-date value using market conventions (such as day-count and date rolling) and then modified by the provider’s calculation rules (including spread-like adjustments and special “triple” rollover on specific roll dates).
Because providers can use different inputs and conventions, the only value you can rely on is the one shown on your specific account, along with the documentation that explains how that number is computed.
Mechanics: what rollover is and what it uses
1) Interest-rate differential, stated in plain terms
Start with this idea: if USD interest rates are higher than CHF interest rates, the side that benefits from the higher-rate currency tends to receive rollover when holding that exposure (and vice versa). For USD/CHF, “holding” means you maintain exposure to one currency against the other past the platform’s roll point.
However, the theoretical interest difference is not the final rollover shown by every platform. In practice, rollover is computed using additional conventions:
- Which interest-rate benchmarks are used (the provider may map USD and CHF to specific reference rates).
- Day-count conventions (how days are counted in the interest calculation).
- Conversion to the account’s quoted terms (how the interest value becomes a money amount for the specific trade size and quote format).
2) Quote convention and position direction
USD/CHF is quoted as USD versus CHF. Rollover sign depends on whether you are long the base currency (USD) or long CHF (depending on whether your platform defines long/short relative to the quote). So rollover isn’t “pair-level only”; it’s pair + direction + provider sign convention.
To verify direction logic on your account, compare rollover on a small position for each direction (with the same size and the same roll date) and confirm that the sign matches your provider’s documented convention.
3) The roll date rule and why “triple swap” appears
Even if the interest differential is stable, the rollover applied on a given calendar day can differ. Many providers apply an expanded rollover on certain roll dates so that interest is accounted for over multiple calendar days.
A common convention is a triple-swap on a day that covers a weekend gap, but the exact day and the exact multiplier depend on the provider’s roll schedule.
Assumptions you need to state when modeling:
- What counts as the provider’s roll point (time zone and cutoff).
- Whether the specific date you’re modeling uses a standard or special rollover multiplier.
- Whether rollover is shown as a net number after any provider adjustment.
4) Provider adjustments and displayed rollover
The displayed rollover is often not a direct translation of the raw interest-rate differential. Providers may incorporate adjustments such as:
- internal markups/spreads applied to the swap rate,
- cost offsets related to execution and pricing models,
- rounding rules that vary by account currency and position size.
Material limitation: without your provider’s documentation for their formula and rate sources, you cannot derive the displayed number precisely from only public interest rates.
Evidence or example (with explicit assumptions)
Below is a simplified example that shows the structure of a calculation, not a guaranteed real-world result.
Assumptions (you must replace these with your provider’s documented values):
- USD reference rate is higher than CHF reference rate.
- The provider uses a specific day-count convention and converts annual interest to a daily amount.
- Your date is a standard roll date (not a special triple-swap date).
- The provider’s displayed rollover equals the theoretical differential interest adjusted by a provider-specific swap rate.
Example structure:
- Compute daily interest amounts for USD and CHF exposure using the day-count convention.
- Take the difference (USD daily interest minus CHF daily interest) for the side that benefits from USD.
- Convert that interest difference into the trade’s money amount using the instrument’s contract/lot sizing and quote conversion rules.
- Apply the provider’s direction sign (long/short) and their swap-rate adjustment.