Understand
The Carry Trade and the Borrow Are the Same Position
Every carry trade has a mirror image. When one side is collecting yield, the other side is paying for dollar access. They are the same position entered from opposite sides. High funding and a wide basis make carry attractive and borrowing expensive. Low funding and a narrow basis make borrowing cheap and carry thin. The environment tells you which side to be on. What you need tells you which direction to run it.
There are two instruments you can use: the perpetual futures contract and the expiring quarterly futures contract. They work the same way structurally but they price the spread differently. The perp rate floats with market sentiment every settlement period. The expiry basis is locked at entry and decays to zero by the settlement date. Understanding both, and how to compare them, is what this lesson covers.
Spot vs Perp: The Floating Rate Structure
The spot-perp spread is the most accessible structure. You hold spot BTC and take an offsetting position in the perpetual futures contract of equal BTC notional. The position is delta neutral: BTC price moves cancel out between the two legs. What remains is the funding rate.
Carry: collect the funding
Hold spot BTC. Short the BTC-USD perpetual in equal notional. Your short perp collects the funding payment from longs every settlement period. This makes sense when funding is elevated, the Regime 1 environment from Lesson 2. At 0.03% per 8h the annualized yield is 32.85%. You are being paid to be short leverage.
Borrow: pay the funding
Sell spot BTC to raise dollars. Buy the BTC-USD perpetual in equal notional. Your long perp pays the funding rate at each settlement, but you have dollar liquidity without a lender. This makes sense when funding is low. Your borrow cost is whatever the current funding rate is. It could be near zero, at the interest rate floor, or anywhere in between. The rate floats with the market for as long as you hold the position.
Same position. If you are short the perp you collect funding. If you are long the perp you pay it. High funding: run the carry. Low funding: run the borrow. The rate is your signal.
The critical characteristic of the perp structure is that the rate resets every settlement period. It can go up or down. If you are collecting carry and sentiment turns negative, the funding rate compresses or flips and your yield disappears. If you are borrowing and sentiment turns bullish, the funding rate rises and your borrow cost increases. You are exposed to rate movement for as long as you hold the position. There is no lock. The perp is a floating rate instrument in both directions.
Spot vs Expiry: The Fixed Rate Structure
The spot-expiry spread works the same way but uses an expiring quarterly futures contract instead of the perpetual. The expiry trades at a premium above spot in contango markets. That premium decays to zero by the settlement date regardless of where price goes. When you enter the trade you lock in the annualized rate at that moment. It cannot change.
Carry: collect the basis
Hold spot BTC. Short the quarterly expiry at the current futures price. The basis, the premium the futures trades above spot, converges to zero at expiry and you collect it. This makes sense when the annualized basis is attractive. At $900 basis on a $66,500 spot with 74 days to expiry the locked yield is 6.67% annualized. It will not move.
Borrow: pay the basis
Sell spot BTC to raise dollars. Buy the quarterly expiry at the current futures price. You pay the basis as your effective borrow cost. The rate is fixed from entry. This makes sense when the annualized basis is low and you want to lock it in before it rises. At 6.67% annualized you have borrowed dollars at a fixed rate for 74 days with no lender.
Same position. If you are short the expiry you collect the basis as it converges. If you are long the expiry you pay it. High basis: run the carry. Low basis: run the borrow. The annualized basis is your signal.
The critical characteristic of the expiry structure is that the rate is fixed the moment you enter. The futures price will move up and down relative to spot after you put the trade on. That is normal and expected. It does not matter. What matters is that the basis must converge to zero by the settlement date. The contract expires at spot. That convergence is guaranteed by the settlement mechanics regardless of what price does in between. The yield you locked in at entry is the yield you collect. The borrow cost you locked in at entry is the borrow cost you pay. The expiry is a fixed rate instrument in both directions.
Reading the Environment
The funding regime from Lesson 2 and the annualized basis together tell you which environment you are in and which direction to run the trade.
| Environment | Funding | Basis | Carry trade | Borrow trade |
|---|
| High carry |
High positive (Regime 1) |
Elevated |
Both legs pay you. Short perp or short expiry. Pick the richer leg. |
Expensive. You pay elevated rates to access dollars. |
| Near baseline |
Near floor (Regime 2) ~11% annualized |
Low |
Thin. Not worth running after execution costs. |
Moderate. Borrow cost at the interest rate floor, around 11% annualized on the perp. Expiry basis may be lower. Check BNOC. |
| Low carry |
Suppressed (Regime 3) 0–4% annualized |
Low |
Too thin to run. Carry does not cover execution costs. |
Cheap. This is the borrow environment. Linear perp funding runs 0 to 4 percent annualized. Both legs let you access dollar liquidity at low cost. |
| Negative funding |
Negative (Regime 4) |
Varies |
Short perp pays you nothing, may cost you. Use expiry if basis is positive. |
Long perp is collecting funding. Unusual borrow where the market pays you. |
BNOC: Which Leg Is Richer
Once you know which direction to run (carry or borrow), BNOC tells you which instrument is pricing the spread more generously and whether the difference between them is large enough to run both legs simultaneously as a delta-neutral spread.
Basis net of carry is the annualized perpetual funding rate minus the annualized expiry basis. A positive BNOC means the perp is pricing carry richer than the expiry. The perp is the expensive leg. If you are running carry you short the perp and long the expiry to capture the differential. If you are running a borrow, positive BNOC means the perp borrow is more expensive, use the expiry instead.
| BNOC | What it means | Carry trade | Borrow trade |
|---|
| Large positive |
Perp is expensive. Retail crowding in the perp vs institutional expiry market. |
Short perp, long expiry. Delta neutral. Earn the differential as it compresses. |
Borrow via expiry, not perp. The expiry rate is cheaper. |
| Large negative |
Expiry is expensive. Institutional hedging demand has pushed the basis above the perp rate. |
Short expiry, long perp. Delta neutral. Earn the differential as it compresses. |
Borrow via perp, not expiry. The perp rate is cheaper. |
| Near zero |
Both legs priced equivalently. No meaningful spread between them. |
Run whichever single leg annualizes above your execution cost threshold. |
Run whichever leg offers the lower annualized cost. |
BNOC does not tell you whether to run carry or a borrow. The environment does that. BNOC tells you which leg of the carry market is priced more richly, and whether the spread between them is wide enough to trade the differential delta-neutral rather than just running a single leg.
Apply
Reading the Setup Before Every Trade
Before entering any carry or borrow structure, run through this sequence in order.
01
Check the funding regime using Lesson 2. Is funding high positive (Regime 1), suppressed below the interest rate floor (Regime 3), or negative (Regime 4)? Regime 1 is a carry environment. Regime 3 and 4 are borrow environments. Regime 2 is neutral: carry is thin and borrow rates are at the floor.
02
Annualize the perp funding rate: per-period rate times (24 divided by settlement interval hours) times 365. If the annualized rate is above 15 to 20 percent, carry is open on the perp leg. Below 12 percent, it is thin after execution costs.
03
Annualize the expiry basis: (futures minus spot) divided by spot, divided by (days to expiry divided by 365). This is the locked yield on a spot-expiry carry or the locked cost on a spot-expiry borrow. Know this number before comparing to the perp.
04
Calculate BNOC: annualized perp rate minus annualized expiry basis. If BNOC is large and positive, the perp is rich. For carry: short perp, long expiry. For borrow: use the expiry leg. If BNOC is near zero, run the single leg with the better annualized rate for your direction.
05
If running a borrow: before withdrawing any cash, calculate your liquidation price on the long derivatives leg. Confirm you have at least a 20 to 30 percent buffer between spot and liquidation. Size the withdrawal accordingly.
Tax warning (borrow only): selling spot BTC to raise dollars is a taxable disposition. The capital gain is calculated from your original acquisition cost, not the futures price. Know your cost basis before executing the borrow structure. Consult a tax advisor if you are sitting on significant unrealized gains.
Case Study
Same Market, Two Environments, Two Different Trades
The same BTC market produces completely different carry and borrow economics depending on the environment. The Q3 2025 high-funding environment and the mid-2026 post-cascade environment show both extremes.
As BTC approached $100,000 in Q3 2025, perpetual funding spiked above 0.05 percent per 8-hour settlement, 54.75 percent annualized, sustained for weeks. The September quarterly basis was running approximately 40 percent annualized. BNOC: +14.75 points. Carry environment, perp is the richer leg.
Trader A holds 1 BTC. She wants to earn yield without selling her position. She checks both legs. The perp is at 54.75 percent annualized. The September expiry basis is at 40 percent annualized. BNOC is +14.75, meaning the perp is pricing carry richer by nearly 15 points. She shorts the perp against her spot BTC. Her position is delta neutral. She collects 54.75 percent annualized on the notional. The crowd of leveraged longs pays her every 8 hours. She could have shorted the expiry instead and collected 40 percent locked, but BNOC told her the perp was the better leg in this environment. This was not the environment to be a borrower. Anyone needing dollars in Q3 2025 was paying above 40 percent annualized for the privilege.
Following the June 2026 liquidation cascade, linear USDT perp funding compressed sharply. The 30-day actual average across major exchanges ran 2 to 4 percent annualized, with 1-day readings briefly going negative. The September quarterly basis had compressed to approximately 3 percent annualized. BNOC was near flat. No carry trade worth running. Both legs are cheap. This is a borrow environment.
Trader B holds 1 BTC at $66,500. He needs $20,000 in cash. He sells 0.30 BTC at $66,500, raising $19,950, and withdraws it. He simultaneously buys 0.30 BTC notional in futures to preserve his price exposure on the BTC he sold. His remaining 0.70 BTC stays in the account as collateral for the long futures position. That 0.70 BTC is worth $46,550. His loan is $19,950. His LTV is $19,950 divided by $46,550, or 43 percent. That is well inside the 75 percent threshold where liquidation risk becomes meaningful. He decides how much buffer he needs based on his own risk tolerance. The lower the LTV the more cushion before the exchange closes the position. On instrument choice: the perp is running 2 to 4 percent annualized now but floats. If sentiment turns bullish his borrow cost rises. The expiry locks in 3 percent annualized for 74 days. He chooses the expiry. Depending on his original acquisition price, selling the 0.30 BTC may be a taxable event. Consult a tax attorney. We are not tax lawyers.
Key Takeaway
The Environment Tells You the Direction. BNOC Tells You the Leg.
High funding and high basis: carry environment. Both legs pay you to be short. BNOC shows which leg is richer and whether a perp-vs-expiry spread is worth running. Low funding and low basis: borrow environment. Both legs let you access dollars cheaply. BNOC shows which leg is cheaper and whether to run a single-leg borrow or a spread. The carry trade and the borrow trade are always the same position entered from opposite sides. The regime tells you which side to be on.