Direct answer
Rollover for Yen crosses is the interest adjustment applied when you hold an FX position past a specified daily “roll” moment. Conceptually, it depends on the interest-rate difference between the two currencies in the pair, the position direction (long vs short), and the platform’s rollover convention (commonly including a larger “triple-swap” on one weekday to cover the weekend).
Because exact numbers vary by provider and account rules, the most reliable way to understand rollover for a Yen cross is to map the calculation into components: (1) the interest-rate inputs, (2) the conversion of those inputs into a per-day (or per-period) value, (3) the direction sign, and (4) any provider-specific swap/fee adjustments and special-day multipliers.
Mechanism or definition
An FX position held overnight exchanges the interest advantages (and disadvantages) implied by the two currencies’ rates. In many retail FX contexts this is shown as “swap,” “rollover,” or “swap rate.” The key inputs are:
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Two currencies and their rates: For a Yen cross, one currency is typically Japanese yen (JPY) paired with another currency (for example, USD/JPY is not a “cross” in the same way as minor-to-minor pairs, but the rollover logic is similar). The rollover aims to reflect the interest-rate gap between JPY and the other currency.
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Position direction: If you are effectively long the base currency of the pair, you generally receive the interest differential; if you are short the base currency, you generally pay it. “Generally” matters because the published swap can incorporate adjustments beyond the pure theoretical interest differential.
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Time and day convention: FX value dates and settlement timing create a daily rollover. Providers often apply a larger rollover on days that bridge the weekend so that interest for additional calendar days is represented.
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Platform adjustments: Many platforms publish a swap/rollover figure that already includes pricing model details, costs, or internal adjustments. This means the displayed swap is often not exactly equal to a simple “interest-rate difference × notional” formula.
A simple model (with explicit assumptions)
Assume a provider uses:
- a per-day rollover based on the interest-rate differential,
- a standard day multiplier of 3 on the rollover day that covers the weekend,
- swap sign based on whether you hold long or short.
Then a conceptual (not guaranteed exact) structure is:
- Interest differential component: reflects (rate of currency A − rate of currency B) for the pair.
- Direction sign: + for the side expected to earn the differential, − for the side expected to pay.
- Notional scaling: converts the interest differential into money terms using the position size.
- Day multiplier: applies 1× normally, 3× on the special day.
- Provider adjustment: adds or subtracts any extra swap/fee component included by the platform.
Evidence or example
Because there are no fixed public numbers in your question, a useful way to verify the calculation is with a controlled “paper” example and then a real statement check.
Example: how triple-swap changes the amount
Assume a Yen cross has a provider-published daily swap of “small positive” when you are long and “small negative” when you are short (the actual sign and magnitude are pair- and provider-specific).
- If you hold overnight on a regular day, you get (or pay) 1× the daily amount.
- If you hold over the day that triggers the triple-swap, you get (or pay) roughly 3× the regular overnight amount.
This behavior is the main practical feature traders notice: the rollover is not uniform across days because the calendar-to-settlement mapping changes.
Example: broker/platform adjustment vs pure interest gap
Suppose the theoretical interest differential suggests a certain sign (you would expect to earn). If the provider’s published swap is smaller than the pure model, larger than the pure model, or even flips sign, then the difference likely comes from provider-specific adjustments (for example, their swap pricing inputs or additional costs).
The takeaway is methodological: the published swap value is the authoritative figure for that provider/account, while theoretical interest-rate gaps help you understand direction and relative size.
Limitations and risks
- Provider/account differences: Swap can be computed and displayed differently across platforms, account types, and execution models. Even if two sources quote “the same pair,” their rollover numbers may differ.