The USD carry trade seeks to earn income from the interest-rate difference between two currencies, but the result depends on much more than the headline policy rates. This guide shows how to estimate carry, account for rollover and forward pricing, compare carry with volatility, and decide when a currency pair needs to be reviewed again.
Overview
A currency carry trade generally involves buying a currency with a relatively higher interest rate and selling, or funding the position with, a currency with a relatively lower interest rate. The trader hopes to collect the interest-rate differential while also avoiding a damaging exchange-rate move.
In a USD carry trade, the U.S. dollar may be the high-yielding currency or the funding currency, depending on the pair and the prevailing rate cycle. For example, buying USD against a lower-yielding currency may create positive carry before trading costs. Selling USD against a higher-yielding currency may also be described as a carry position, but it carries the opposite exchange-rate exposure. The direction of the trade matters as much as the size of the rate gap.
Carry is not a guaranteed return. A currency can fall by more than the interest earned, turning a seemingly attractive yield into a loss. Leverage can magnify that outcome, while widening bid-ask spreads, broker financing terms, political risk, and sudden changes in market volatility can alter the trade quickly.
The most useful comparison is therefore not “which currency has the highest interest rate?” It is “which pair offers a reasonable expected carry after costs relative to its potential drawdown?” That question requires a repeatable worksheet rather than a one-time ranking.
For background on broader dollar drivers, compare this framework with how DXY, Treasury yields, and Fed policy inform a U.S. dollar forecast. Carry analysis is narrower: it focuses on the financing and risk characteristics of a specific currency pair.
How to estimate
Start with the simple annualized interest differential:
Estimated gross carry = long-currency interest rate − short-currency interest rate
If a trader is long USD and short another currency, use the relevant USD funding or deposit rate and the corresponding rate for the short currency. The exact rate used by a broker may differ from a central-bank policy rate. Retail platforms commonly calculate overnight financing from their own reference rates, markups, contract conventions, and three-day weekend adjustments.
Convert the annual estimate to a daily approximation when needed:
Estimated daily carry = annualized rate differential × position notional ÷ day-count basis
The day-count basis may be 360 or 365 days, depending on the product and broker. This calculation is only an initial estimate. A more realistic net estimate is:
Estimated net carry = gross carry − broker financing adjustment − spread − commission − expected slippage − hedging costs
Forward points provide another way to assess the market’s pricing of the rate difference. A forward exchange rate can trade above or below the spot rate because of interest-rate parity, liquidity, supply and demand, and market expectations. Forward points are not a free profit. They represent part of the expected financing relationship between the two currencies and can change as rates, liquidity, and risk premiums change.
For a practical comparison, calculate three figures for each candidate pair:
- Net annualized carry: the estimated financing income or cost after known charges.
- Expected or observed volatility: a consistent measure, such as a 20-day or 60-day annualized reading, using the same method for every pair.
- Carry-to-risk ratio: net annualized carry divided by the selected volatility measure.
The carry-to-risk ratio is a screening tool, not a forecast. A high ratio may reflect unusually low recent volatility, an unstable rate differential, or risks that are not captured by a simple historical measure.
Inputs and assumptions
A monthly carry review should record the following inputs on the same date and, where possible, from consistent sources:
| Input | What to record | Why it matters |
|---|---|---|
| Pair and direction | For example, long USD/short foreign currency | Carry changes when the trade direction changes. |
| Reference rates | Relevant policy, money-market, or broker rates | Headline central-bank rates may not equal executable financing rates. |
| Forward points | Forward premium or discount for the selected maturity | Shows how financing is reflected in market pricing. |
| Rollover terms | Daily swap, weekend adjustment, and contract size | These determine realized financing income or cost. |
| Transaction costs | Spread, commission, and estimated slippage | Small costs can materially affect short holding periods. |
| Volatility | A defined historical or implied volatility measure | Provides context for potential price movement. |
| Drawdown limit | Maximum tolerable loss and position size | Prevents the interest income from dictating excessive leverage. |
Use like-for-like assumptions. Comparing a broker’s quoted overnight swap on one pair with a central-bank rate on another can create a misleading ranking. If a data point is unavailable, label it as an estimate and use a range rather than false precision.
Also separate rate risk from currency risk. Central banks can change their expected paths, and markets can price those changes before an official decision. A pair with positive carry today may have less attractive forward pricing tomorrow. Political events, fiscal concerns, commodity shocks, and safe-haven demand can also overwhelm the interest differential.
Emerging-market currencies may show larger nominal carry than major currencies, but that can reflect higher inflation, lower liquidity, convertibility concerns, or greater sensitivity to global risk appetite. A higher rate should be treated as compensation for risk, not proof of a superior opportunity.
Worked examples
The following examples are hypothetical and are intended to demonstrate the method, not to describe current market conditions or recommend a pair.
Example 1: Estimating gross and net carry
Assume a trader buys the equivalent of $10,000 of a currency pair. The long currency has a reference rate of 5.00%, while the short currency has a reference rate of 2.00%. The gross differential is therefore 3.00% per year.
Using a 365-day basis:
- Gross annual carry: $10,000 × 3.00% = $300.
- Approximate gross daily carry: $300 ÷ 365 = $0.82.
- Approximate gross monthly carry over 30 days: $0.82 × 30 = $24.60.
Now assume the broker’s financing adjustment reduces the annualized result by 0.75 percentage points, and estimated trading costs for entering and exiting total $12. The adjusted annual carry rate is 2.25%, producing approximately $225 before the entry and exit costs. For a 30-day holding period, the rough net result would be the financing income for that period minus the $12 transaction cost. The actual platform result could differ because rollover is applied daily and may include a special weekend adjustment.
Example 2: Comparing carry with volatility
Suppose Pair A has an estimated net carry of 2.4% and annualized volatility of 8%. Its simple carry-to-risk ratio is 0.30. Pair B has net carry of 5.5% but volatility of 25%, producing a ratio of 0.22.
Pair B offers more income in percentage terms, but Pair A has the stronger simple carry-to-risk reading in this illustration. That does not make Pair A safer or more profitable. The comparison should prompt further checks: maximum historical drawdown, liquidity during market stress, sensitivity to central-bank decisions, and the effect of a one-percent adverse currency move.
Example 3: Testing an adverse move
If a $10,000 position earns an estimated 2.25% annualized net carry, the expected annual financing income is about $225 before taxes and unanticipated costs. A 3% unfavorable exchange-rate move would reduce the position by approximately $300, more than offsetting that annual carry. This simple stress test illustrates why position size and stop or exit rules matter more than the headline yield alone.
When to recalculate
Recalculate the USD carry trade worksheet at least once each month and after any event that can change the rate differential or the risk profile. Important triggers include a Federal Reserve decision, another central-bank decision, a material change in expected policy rates, a sharp move in Treasury yields, or a significant change in broker rollover terms.
Also review the position after major inflation and employment releases, particularly when those reports alter expectations for interest rates. The CPI, PCE, and jobs data guide can help organize the data calendar. For pairs linked to commodities, review oil, copper, and China-sensitive developments as described in the USD and commodity currencies analysis.
Use this monthly worksheet:
- Record the pair, position direction, notional value, and entry exchange rate.
- Update both reference rates and the broker’s actual rollover quote.
- Record forward points for the relevant maturity, if available.
- Subtract spreads, commissions, financing markups, and expected slippage.
- Update the chosen volatility measure and calculate the carry-to-risk ratio.
- Run adverse-move tests, such as a 1%, 3%, and 5% currency move against the position.
- Check the next central-bank meetings, inflation releases, and employment reports.
- Reduce, hold, or close the trade only after comparing the updated reward with the revised drawdown risk.
Keep a dated record of every version. This makes it easier to distinguish a genuine change in carry from a change caused by a new calculation method. Before taking a position, consider how much of your portfolio is already exposed to the U.S. dollar, global risk appetite, or the same central-bank theme. A currency-risk checklist can help place the trade in that broader context.
The best carry trade is not necessarily the pair with the largest interest-rate gap. It is the position whose financing income, exchange-rate exposure, liquidity, and drawdown risk remain acceptable under realistic assumptions. Revisit the numbers whenever rates or volatility move, rather than treating a previous ranking as permanent.
