What rollover means for USD/CAD
In forex, rollover (also called swap) is an amount that accounts for the interest-rate difference between two currencies when a position is held from one trading day to the next. Conceptually, if you hold a long position on one currency versus the other, the rollover attempts to reflect the economic effect of receiving interest on the currency leg you effectively own and paying interest on the currency leg you effectively finance.
For USD/CAD, rollover is therefore tied to the relative interest rates of USD and CAD, and to whether your position is long USD vs. long CAD (depending on how the provider defines the pair direction for swap). The mechanics are stable: the amount is driven by interest-rate inputs and conventions, while the exact number you see is affected by provider-specific calculations and any included costs.
How the calculation is typically constructed
A common way to think about rollover is as a net interest differential, converted into the account currency using pair pricing and then adjusted by conventions.
1) Choose the direction
USD/CAD is quoted as USD price in CAD. A position long USD/CAD is economically aligned with “long USD vs. short CAD,” while short USD/CAD aligns with “short USD vs. long CAD.” The rollover sign (positive or negative) typically follows that direction: you are generally credited when the “long leg” has the more favorable interest economics under the provider’s model, and charged otherwise. Exact sign conventions can vary by provider.
2) Start from interest-rate inputs
Rollover models use interest-rate inputs for each currency leg. These inputs are often conceptually related to money-market rates or benchmark rates that represent the cost of funding and the return on the opposite leg. The stable idea is a difference between the USD and CAD interest expectations, converted into a daily accrual.
A simplified structure looks like:
- Daily accrual component ≈ (rate_USD − rate_CAD) × position_notional × time_fraction
- Then apply conversion factors so the result is expressed in the provider’s reporting currency for that contract/account.
Because the exact formula differs across providers, you should treat this as a framework: the difference of rates is the core driver, but the how (day-count, scaling, and which specific rates are used) depends on the provider’s published rollover methodology.
3) Apply time conventions and the rollover window
Forex rollover is defined around when positions are considered to have been held “over” the relevant daily cutoff. Providers may apply different day-count conventions (how many days the accrual is spread over) and different rules for when the swap is applied relative to the trading session.
4) Account for “triple-swap” day handling
Many systems use a convention where rollover from the last business day before a market closure is larger, often described as a triple-swap effect. The stable reason is that the position accrual spans multiple days because one or more days have no normal rollover application.
In practice, for USD/CAD the provider may apply a multiplier to the usual single-day rollover on the day(s) that bridge the weekend or similar gaps. The important limitation is that the multiplier and the exact weekday schedule are provider-specific.
Evidence or example you can reproduce (with clear assumptions)
Because you should not rely on live broker numbers, you can reproduce the logic using placeholders and a clearly stated assumption set.
Assume:
- You hold USD/CAD long for one rollover day (not including any triple-swap bridging).
- The provider uses interest-rate inputs that can be summarized as an annualized USD-minus-CAD differential.
- The provider converts the differential to a daily amount using a day-count fraction f (for example, a fraction based on how many days are used for the year in their model).
Then a reproducible framework calculation is:
- Compute the rate differential: Δr = r_USD − r_CAD.
- Convert to a daily rate: r_daily = Δr × f.
- Apply a notional scaling to get a raw interest differential in quote terms, then convert to the account reporting terms using the pair price and contract specifications.
- Apply the provider’s sign convention based on whether the position is long or short the pair.