Direct answer: what rollover means for minor pairs
Rollover (also called swap) is the amount a broker charges or credits when you hold a forex position overnight. For minor pairs, the calculation follows the same basic idea: it approximates the overnight interest-rate difference between the two currencies in the pair, then applies the broker’s specific conventions (such as which day counts as the weekend and whether a triple-swap rule is used).
Because rollover is derived from rates and contract conventions, it is an estimate—not a guaranteed cost or credit. The exact amount depends on the broker’s swap schedule, the trade’s direction (buy vs sell), and how the broker defines the holding period boundaries.
Mechanism or definition: the simple interest-gap model
A practical way to understand rollover for any currency pair is to separate three parts:
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Interest-rate inputs (the “gap”) In simplified form, the model compares the short-term interest expectations for the base currency versus the quote currency. If the base currency’s relevant rate is higher than the quote currency’s rate, holding a long position can tend to produce a credit; if lower, it can tend to produce a charge. The opposite typically applies for a short position.
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Direction and settlement convention Rollover is not symmetric across buy and sell. It depends on whether you are effectively long or short each currency leg and on the broker’s treatment of the trade’s value date (the day the contract is considered settled for interest purposes).
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Broker adjustments and sign conventions Brokers usually publish a swap schedule that maps pair, direction, and sometimes account or instrument type to an overnight swap amount. Internally, this often incorporates the interest-rate inputs but also includes broker-specific adjustments.
Example model (assumptions stated)
Assume a broker uses a daily rollover rate derived from an interest-rate gap and that the position is held exactly for one broker-defined overnight period. A simplified estimate could be:
- Estimated rollover ≈ (daily interest gap) × (notional amount) × (contract scaling) Then apply the sign based on trade direction and the broker’s published convention.
This model helps you explain the logic, but it should not be treated as a substitute for the broker’s actual swap table.
Evidence or example: why “triple-swap” matters on minor pairs
Many rollover schedules include a triple-swap convention on a particular weekday. The reason is mechanical: the spot-value and settlement timing often cause holding over the weekend to involve a longer effective accrual period than a normal one-day overnight hold.
A clear, non-empirical way to state the convention
- On the “triple-swap” day, the broker may apply an effective rollover amount equal to roughly three daily accruals instead of one.
- On other days, rollover is typically closer to one daily accrual.
Example model (assumptions stated)
Assume:
- Normal daily rollover estimate = X per overnight hold.
- Triple-swap day replaces the weekend-accrual gap. Then the rollover for that day is often approximated as 3X (then direction and sign still apply).
Even if you use this framework, the exact multiplier and the day it applies can differ by broker and by account/instrument type, so the most reliable verification is the broker’s published swap specification for the specific minor pair.
Limitations and failure modes: what can break the estimate
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Broker policy can differ from the simple interest-gap model A broker may adjust rates, apply proprietary markups, or use specific contract terms. That means your calculated estimate may not match what you see.
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Rollover depends on when the broker considers the position “held overnight” If your execution timing or the broker’s value-date rules differ from your assumption, the swap can shift.
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Triple-swap timing and multipliers can be broker-specific Some schedules treat weekend rollover as multiple days in a way that may not equal exactly three in all cases.
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Noisy real-world implementation Even with the same stated interest-gap inputs, differences in pricing, internal hedging assumptions, and order of operations can change the resulting swap figure.
Verification or next question: how to confirm independently
To verify the rollover logic for minor pairs without relying on predictions, do two checks:
- Use the broker’s published swap schedule for the exact minor pair and your trade direction.