Carry Trade Strategy: Yield Differentials, Funding and Spot Losses
A currency carry trade strategy borrows in one currency to hold an income-producing asset in another. Its profit is the investment proceeds converted back into the funding currency, minus the loan repayment and costs. A positive yield gap can still produce a loss when the investment currency falls. Retail forex positions use broker financing credits or debits instead of a separate loan and deposit.
Review Pine Script AI Coding AgentKey Takeaways
- Use executable borrowing and investment rates, or the broker's actual swap schedule, rather than subtracting central-bank policy rates.
- Define the exchange-rate quote before calculating returns. Here, AUDJPY means JPY paid for one AUD; a lower quote hurts a long-AUD carry trade.
- In the hypothetical one-year example, a 5% fall in AUDJPY turns JPY 40,000 of flat-spot profit into a JPY 12,500 loss before costs.
- A funding renewal can change both the interest rate and access to credit. Leverage can force liquidation before an investment matures.
- A TradingView price backtest needs a separate, dated financing ledger to evaluate total carry returns.
Identify the investment and the funding contract
The San Francisco Fed describes the cash version as borrowing a funding currency, converting it, and lending the target currency. Record the actual investment instrument and its maturity alongside the loan terms. A deposit rate, bond coupon and bond yield are different inputs: a bond sold before maturity also has a sale price, accrued interest and possible credit loss. A coupon alone is not the total return. The deposit example below assumes repayment in full and isolates currency and financing effects.
- Investment leg: currency, amount paid, interest or coupon dates, reinvestment assumptions, exit value and withdrawal restrictions.
- Funding leg: borrowed principal, quoted borrowing rate, day-count basis, maturity, collateral terms and renewal conditions.
- Conversion leg: entry and exit exchange rates, their quote direction, bid/ask spread and account-currency conversion.
- Policy rates describe monetary policy. They do not establish the deposit rate, borrowing spread or swap rate available to this account.
Reconcile both legs in JPY before calculating a return
This is a hypothetical one-year cash trade, not a current quote or a broker offer. Borrow JPY 1,000,000 at 1% simple annual interest. At S0 = 100 JPY per AUD, buy AUD 10,000 and place it in a one-year deposit at 5% simple annual interest. Assume both contracts run to maturity, with no tax, fees, default or interim cash flows. The investment pays AUD 10,500; the loan requires JPY 1,010,000. If ST is the closing JPY-per-AUD quote, profit in JPY = AUD 10,500 × ST − JPY 1,010,000.
- General formula: profit in funding currency = (B / S0) × (1 + rI × T) × ST − B × (1 + rF × T) − C. B is borrowed funding currency, rI and rF are decimal annual rates, T is years, and C is total costs expressed in funding currency.
- Flat spot, ST = 100: JPY 1,050,000 investment proceeds − JPY 1,010,000 repayment = JPY 40,000 profit, or 4% of borrowed principal.
- AUD falls 5%, ST = 95: JPY 997,500 proceeds − JPY 1,010,000 repayment = JPY 12,500 loss, or −1.25% of borrowed principal.
- AUD falls 10%, ST = 90: JPY 945,000 proceeds − JPY 1,010,000 repayment = JPY 65,000 loss, or −6.5% of borrowed principal.
- Break-even before costs: ST = 1,010,000 / 10,500 = 96.190476 JPY per AUD. A depreciation of about 3.81% consumes the positive carry.
Why adding 4% carry to a −5% spot return is inaccurate
The AUD interest is also exposed to the closing exchange rate. At ST = 95, the original AUD 10,000 principal loses JPY 50,000 against its entry value. The AUD 500 interest converts to JPY 47,500, while JPY 10,000 of funding interest remains payable. The reconciliation is −50,000 + 47,500 − 10,000 = −12,500 JPY. Adding 4% and −5% would incorrectly give only a 1% loss. With these assumptions, the exact return on borrowed principal is (1 + rI × T) × (ST / S0) − (1 + rF × T).
- With JPY 5,000 of total costs, the flat-spot profit becomes JPY 35,000 and the break-even quote rises to 1,015,000 / 10,500 = 96.666667.
- With zero rates and no costs, profit reduces to B × (ST / S0 − 1). With an unchanged quote and equal rates, profit is zero.
- If the displayed pair is inverted to AUD per JPY, invert the quote before using this formula. A rising funding-currency-per-investment-currency quote has the opposite effect from a rising inverted quote.
Leverage changes the equity loss, not the currency cash flow
Suppose JPY 200,000 of your own capital is reserved as collateral for the JPY 1,000,000 loan. Initial borrowed notional divided by collateral is 5. The collateral earns no interest in this illustration and is separate from the borrowed amount invested. At ST = 90, the same JPY 65,000 loss consumes 32.5% of that capital; at flat spot the JPY 40,000 gain is 20% of capital. These are terminal scenarios assuming the position survives to maturity, not forecasts or margin rules.
- At ST = 75, proceeds are JPY 787,500 and the loan shortfall is JPY 222,500. This exceeds the assumed collateral by JPY 22,500 before costs.
- At 2 times initial notional-to-collateral, JPY 500,000 collateral absorbs the ST = 90 loss as 13%; at 10 times, JPY 100,000 collateral loses 65%.
- Collateral calls, loan covenants or broker close-out rules can end the trade earlier. Check the actual contract; terminal arithmetic does not model the liquidation path.
- A stop order cannot guarantee a fill at its trigger through a gap or an illiquid market. Several carry positions may lose together when they share a funding currency.
Funding renewal and reinvestment change the result
Now replace the one-year contracts with two six-month periods. Assume interest is reinvested in AUD and unpaid funding interest is added to the JPY loan at renewal. The AUD annualized rate is 5% for the first half-year and 3% for the second; the JPY borrowing rate rises from 1% to 4%. Each half-year uses simple interest with T = 0.5. These are assumed contract rates, with no conversion between periods or renewal fees.
- AUD maturity proceeds: 10,000 × (1 + 0.05 × 0.5) × (1 + 0.03 × 0.5) = AUD 10,403.75.
- JPY repayment: 1,000,000 × (1 + 0.01 × 0.5) × (1 + 0.04 × 0.5) = JPY 1,025,100.
- At ST = 100, profit is 10,403.75 × 100 − 1,025,100 = JPY 15,275. At ST = 95, profit is −JPY 36,743.75.
- The second half-year has a negative rate gap, despite positive carry at entry. Do not apply the initial gap to the entire holding period.
- If interest is paid from external cash rather than capitalized, record each payment separately. If funding cannot be renewed, model repayment and the forced sale or withdrawal at that date.
Retail forex swap needs its own ledger
A rolling retail forex position is a different contract from the loan-and-deposit example. OANDA Corporation documents direction-specific financing rates derived from liquidity-provider tom-next rates and an administration adjustment. Rates can change daily; weekend and holiday settlement can create multi-day charges. Its US documentation uses a 5 p.m. ET cutoff. Check your own broker, entity and account terms before applying that convention.
- For an illustrative JPY account, hold AUD 100,000 at 100 JPY per AUD. If a quoted net annual financing rate of +2% applies to the JPY 10,000,000 position value on a 365-day basis, a one-day credit is JPY 547.95; a three-day credit is JPY 1,643.84. These are assumed rates, not an OANDA quote.
- A −2% net rate creates the same amounts as debits. If the broker quotes points or money per lot, use its conversion and contract size instead of this annual-rate formula.
- Retail P&L in account currency = converted spot P&L + signed posted financing − remaining trading costs. Do not subtract a separate loan charge again if the financing amount already includes it; do not count the spread twice if fills already include it.
- Store the charged date, settlement-day multiplier, direction, position size, rate, conversion and posted amount. A credit does not compound the position automatically unless the sizing rule reinvests it.
Build a dated research record before comparing entry rules
BIS research describes how leveraged carry positions can unwind when funding conditions or exchange rates change. Test that possibility directly. Keep price returns, financing, transaction costs and equity drawdowns as separate series before reconciling them. A long AUDJPY chart trade represents long AUD versus JPY; a hypothetical long-MXN versus USD trade would be short USDMXN. Pair labels alone do not identify the income-receiving direction.
- Record only rates and financing terms available at the decision time. Historical policy rates or today's broker swap rate cannot substitute for a missing historical financing series.
- Specify a review schedule and a minimum net-carry assumption before testing. If dated funding evidence is missing, label the result as a cost scenario or a price-only study.
- Stress a 5% and 10% adverse exchange-rate move, negative financing after renewal, a failed renewal, wider spreads and an earlier collateral call. Revalue both legs in the same currency.
- For chart-rule research, write the signal observation time, next eligible fill, sizing rule and exit condition before comparing parameters. Reserve a later period that was not used to choose them.
Use Pineify for chart rules, then reconcile financing separately
The Pine Script AI Coding Agent can help draft and edit observable price rules for a TradingView strategy. Supply an explicit specification, such as evaluating a daily trend filter only after the bar closes and placing the simulated order on the next eligible bar. Review the generated source and its order timing. Strategy Optimizer can compare supported exposed strategy input combinations and export results for analysis. This page supplies a cash-flow research method, not a ready-made Pine carry engine.
- TradingView strategies use a broker emulator. Their commission and slippage settings do not automatically supply the historical loan, deposit or broker swap cash flows described here.
- Reconcile exported trades with dated financing records in a separate ledger. Compare net results and drawdowns after this reconciliation, including the held-out period.
- Pineify does not supply FX loans, deposits, broker execution or a complete multi-currency financing ledger through this workflow. Parameter rankings cannot establish that future carry will be profitable.
Pineify next step
Specify the chart rule you want to investigate
Use Pine Script AI Coding Agent to draft an editable TradingView strategy, then compare inputs with Strategy Optimizer. Keep the funding ledger and net-return reconciliation alongside the price backtest.
Educational research only, not investment advice. All numerical examples use hypothetical rates and omit costs unless stated. They are not historical backtests, current offers or expected returns. Currency moves, credit losses and funding changes can cause substantial losses; leveraged losses can exceed the capital allocated to a position.
Frequently Asked Questions
Is a carry trade an arbitrage?
An unhedged currency carry trade bears exchange-rate risk, so a positive yield gap does not lock in a profit. If you hedge the currency exposure with a forward, use the executable forward price and all costs; do not assume the original yield gap survives the hedge.
Does buying the higher-rate currency guarantee positive swap?
No. The broker's direction-specific financing rate, administration adjustment and account terms determine the credit or debit. Central-bank rates are not a quote for the financing available to you.
How far can the currency fall before carry is wiped out?
In the hypothetical one-year example, the break-even AUDJPY rate is 96.190476 JPY per AUD, down about 3.81% from 100. This follows from converting AUD 10,500 into the JPY 1,010,000 loan repayment. Costs raise the required closing exchange rate.
Can carry lose money while the exchange rate is unchanged?
Yes. Investment income can be smaller than borrowing interest and fees, or retail financing can become a debit. An investment sold below its purchase price can also lose money with a flat exchange rate. Compute actual cash flows rather than relying on the entry-day rate gap.
Does a TradingView backtest include all carry income?
A price strategy does not automatically include historical broker swaps or a loan-and-deposit ledger. Add dated financing and conversion records to the analysis, and label assumed costs clearly. A profitable price backtest alone is not evidence of profitable total carry.