Basis trading is a strategy that profits from changes in the spread between an asset’s spot price and its futures price, rather than from the direction of the market itself. The “basis” is the spot price minus the futures price, and every position, hedge, and tax rule attached to this strategy revolves around whether that number widens or narrows before the futures contract expires. The approach began with agricultural hedgers managing seasonal swings and now dominates parts of the U.S. Treasury market, energy desks, and some digital asset venues.
How the Basis Is Calculated
The spot price is what you would pay to buy the asset today for immediate delivery. The futures price is what you agree to pay for delivery on a set date. Subtract one from the other:
Basis = Spot Price − Futures Price
A positive basis means spot exceeds futures. A negative basis means futures trade above spot. Neither reading is inherently good or bad. What matters is which way the spread moves after you enter the trade, and whether that movement matches your position.
What Drives the Spread
The gap between spot and futures reflects the cost of carrying the underlying asset until the contract expires. For physical commodities, carrying costs include storage, insurance, and spoilage risk. For financial instruments, the costs shift to financing charges and the opportunity cost of tied-up capital.
In bond markets, that financing cost is often expressed as an implied repo rate: the annualized return from buying a bond, selling a futures contract against it, and delivering the bond at expiration. When the implied repo rate exceeds your actual borrowing cost, the trade is theoretically profitable. When it falls below your funding cost, the spread isn’t wide enough.
Income from the underlying works in the opposite direction. Dividends on equities and coupons on bonds reduce the effective cost of carry because you’re earning a return while holding the spot position. The higher the yield, the smaller the expected futures premium. This tug between financing costs and asset income is what keeps the basis moving throughout the life of a contract.
Contango, Backwardation, and Convergence
When futures trade above spot, the market is in contango. This is the more common condition, driven by carrying costs priced into longer-dated contracts. When futures trade below spot, the market is in backwardation, often a signal of tight near-term supply or strong immediate demand.
Market condition dictates trade direction. In contango, a trader expecting the premium to shrink would sell the basis (sell cash, buy futures). In backwardation, a trader expecting the discount to narrow would go long the basis (buy cash, sell futures). Both rely on the same force: as expiration approaches, the futures price and the spot price converge. On final settlement day, the two are essentially identical because the futures contract becomes a spot transaction. That convergence is the engine of every basis trade.
Long and Short Basis Positions
Going long the basis means buying the cash asset and simultaneously selling the futures contract. You profit when the basis widens, meaning spot strengthens relative to futures or futures fall faster than spot. Traders usually take this position when the basis is unusually narrow and they expect reversion to a wider historical norm.
Going short the basis is the mirror image. You sell or short the cash asset and buy the futures contract. Profit comes when the basis narrows. This is the position to take when the futures premium looks unusually large and you expect it to compress into expiration.
Either way, you’re largely hedged against broad directional moves in the underlying. If the bond market rallies 2%, the long cash leg gains while the short futures leg loses roughly the same amount, and the reverse holds. Your exposure sits on the spread itself. “Largely hedged” is not “risk-free,” though. Margin calls on the futures leg can force you out of an otherwise sound position before convergence happens, and the basis can move against you longer than your capital allows.
Cash-and-Carry Arbitrage
The cash-and-carry trade is the textbook basis strategy. In a contango market, you buy the spot asset, sell the futures contract, and hold until expiration. At delivery, you hand over the asset you already own to settle the futures. Profit equals the futures premium at entry minus all holding costs.
For this to work, the futures premium must exceed total carry: financing, storage, insurance, and any other expense. When it does, the trade locks in a return that looks a lot like a fixed-income yield. Institutional desks sometimes compare basis returns to repo rates or Treasury bill yields when deciding where to park capital.
The reverse cash-and-carry works in backwardation. You short the cash asset (or lend out securities you already hold) and buy the futures contract. At expiration, you take delivery through the futures and close the short. It only makes sense when the discount on futures is large enough to cover your borrowing cost on the short sale.
The Treasury Basis Trade
The most prominent basis trade in modern finance involves U.S. Treasury bonds. A hedge fund buys Treasuries in the cash market, typically financing the purchase through overnight or short-term repo borrowing, and shorts Treasury futures. The spread is usually tiny, so profitability depends on massive leverage. Funds commonly use repo to finance 90% or more of the cash bond purchase, turning a few basis points of spread into meaningful returns.
Regulators and central banks watch this trade closely because of systemic risk. The leverage is real and the funding is short-term. If repo markets tighten or margin requirements spike during a volatility event, funds can be forced to unwind rapidly, dumping Treasuries into a market that may already be stressed. Disruptions of this kind were a factor in the March 2020 Treasury market dislocation. Because Treasuries anchor the global risk-free rate, forced unwinds can ripple across asset classes and borders.
For individual traders, the Treasury basis trade is largely inaccessible: the capital scale and institutional repo access aren’t available at retail. Understanding it still matters, because Treasury basis activity influences bond yields, futures pricing, and overall government bond market liquidity.
Account Requirements and Margin Risk
Running a basis trade requires a brokerage account with both securities and futures capabilities, often meaning separate but linked accounts under one firm. The futures leg requires posting margin, which is a performance deposit rather than a down payment. Levels vary by contract. Customer maintenance margin on Cboe Volatility Index futures recently stood at $9,768 per contract, while Bitcoin Index futures required $1,683.
On the securities side, Federal Reserve Regulation T sets initial margin at 50% of the purchase price for most marginable securities. FINRA Rule 4210 sets minimum maintenance margin at 25% of current market value for long equity positions, though most firms impose higher house requirements.1FINRA. FINRA Rule 4210 – Margin Requirements
The real danger is what happens when prices move against you. Brokerages are not required to warn you before liquidating positions to meet a margin deficiency. They can sell securities in your account without issuing a margin call first, and they can sell more than what’s necessary to cover the shortfall. They choose which positions to liquidate. Under Regulation T, if you fail to meet the initial margin requirement within three business days and the firm doesn’t grant an extension, liquidation happens automatically.2FINRA. Know What Triggers a Margin Call
Executing the Trade
The critical moment is getting both legs filled at the intended spread. Because you’re entering two positions at once, one side can fill while the other moves against you. This is known as leg risk or execution slippage. Professional desks handle it with spread-order tools that submit both legs as a package, filling only when the target net price is achievable. Retail traders working the legs manually need to move fast and should start with the less liquid side, where slippage is harder to control.
Once both positions are live, management is mostly about monitoring margin and watching the basis. The futures leg is marked to market daily, so your margin balance fluctuates every session even when the overall spread hasn’t moved much. A sharp move in the underlying can trigger a margin call on the futures side while the cash position shows an offsetting gain that doesn’t help you meet the margin requirement in real time.
Closing the trade requires the same coordination. Both legs need to come off at or near the same time. Letting one linger while the other is closed converts a hedged spread into a naked directional bet, a completely different risk profile than what you signed up for.
The 60/40 Tax Rule for Futures
The futures leg often qualifies for favorable tax treatment under Section 1256 of the Internal Revenue Code. A Section 1256 contract includes any regulated futures contract traded on a qualified exchange and subject to daily mark-to-market settlement, along with foreign currency contracts, nonequity options, and certain dealer contracts. Swaps, including interest rate swaps, basis swaps, and credit default swaps, are excluded.3Office of the Law Revision Counsel. 26 USC 1256 – Section 1256 Contracts Marked to Market
Gains and losses on Section 1256 contracts receive blended treatment regardless of holding period: 60% at the long-term capital gains rate, 40% at the short-term rate. For 2026, the long-term rate is 15% for most taxpayers (20% above $545,500 for single filers), while the short-term portion is taxed as ordinary income. That blended figure is significantly better than paying ordinary rates on the entire gain, which is what a position held under a year would face under standard rules.3Office of the Law Revision Counsel. 26 USC 1256 – Section 1256 Contracts Marked to Market4Internal Revenue Service. Topic No. 409, Capital Gains and Losses
The catch: Section 1256 contracts are marked to market at year-end. Even if you haven’t closed the position, you report the unrealized gain or loss as if you had sold on December 31. The cash leg does not get this treatment. It follows standard capital gains rules, with the rate depending on your actual holding period. Report Section 1256 results on Form 6781.5Internal Revenue Service. Form 6781 – Gains and Losses From Section 1256 Contracts and Straddles
Straddle Rules and Loss Deferral
Because the cash and futures legs move in opposite directions, the IRS will likely treat the combined position as a “straddle” under Section 1092. A straddle exists whenever you hold offsetting positions in the same or related property. Basis trades almost always qualify.
Straddle classification triggers a loss deferral rule. If you close one leg at a loss while the other leg has an unrecognized gain, you can only deduct the loss to the extent it exceeds the unrecognized gain on the remaining position. Any disallowed portion carries forward, subject to the same limitation.6Office of the Law Revision Counsel. 26 USC 1092 – Straddles
Suppose you close the futures leg at a $10,000 loss, but the cash leg has a $7,000 unrealized gain at year-end. You can deduct only $3,000 of that loss this year. The remaining $7,000 rolls forward. The rule exists to stop taxpayers from selectively realizing losses while sitting on offsetting gains.
The straddle loss deferral rules under Section 1092 replace the standard wash sale rules for positions in a straddle. You won’t face both sets of restrictions on the same position, but the straddle rules are often more restrictive in practice.
For more control over how losses are allocated, you can make an identified straddle election. This requires marking the position as an identified straddle in your records before the close of the day you acquire it. Under this election, a loss on one leg gets added to the tax basis of the offsetting positions rather than being deferred, which can produce a better result when the entire trade is eventually closed.6Office of the Law Revision Counsel. 26 USC 1092 – Straddles
Straddle classification also affects carrying costs. Under Section 263(g), interest paid to finance a straddle position and other carrying charges like storage and insurance cannot be deducted as current expenses. Those costs must be capitalized and added to the property’s basis. Capitalization only applies to the portion of carrying costs that exceed income (interest, dividends, or coupons) received from the straddle positions during the year.7Office of the Law Revision Counsel. 26 USC 263 – Capital Expenditures
Constructive Sale Rules
Section 1259 creates another trap. If you hold an appreciated financial position and then enter a futures or forward contract to deliver the same or substantially identical property, the IRS treats the setup as a constructive sale. You owe tax on the gain as if you had sold the position at fair market value on the date you entered the offsetting contract.8Office of the Law Revision Counsel. 26 USC 1259 – Constructive Sales Treatment for Appreciated Financial Positions
This bites basis traders directly, because buying a bond and shorting a futures contract on the same bond can look exactly like a constructive sale if the bond has appreciated since you bought it. The rule applies to stock, debt instruments, and partnership interests.
There is a narrow escape. The constructive sale is disregarded if you close the offsetting transaction within 30 days after the end of the tax year, hold the appreciated position without reducing risk for 60 days after closing, and your risk of loss remains genuine throughout that 60-day window. All three conditions are mandatory. Miss any one and the constructive sale treatment applies.8Office of the Law Revision Counsel. 26 USC 1259 – Constructive Sales Treatment for Appreciated Financial Positions
Mark-to-Market Election for Professional Traders
Traders who qualify as running a trading business, as opposed to investing, can make a mark-to-market election under Section 475(f). The election converts gains and losses on trading positions into ordinary income and ordinary losses, reported on Form 4797 rather than Schedule D. The biggest advantage is that ordinary losses are fully deductible against other income with no annual cap, unlike capital losses, which are limited to $3,000 per year against ordinary income. Wash sale rules and straddle loss deferral rules also stop applying to positions covered by the election.9Internal Revenue Service. Topic No. 429, Traders in Securities
The tradeoff: you lose the 60/40 blended rate on Section 1256 contracts covered by the election, and you lose long-term capital gains treatment on positions held over a year. For traders who consistently generate short-term gains and occasionally face large losses, the math usually favors electing. For traders with a mix of holding periods, it takes careful analysis.
The deadline is strict. You must make the election by the due date (without extensions) of the return for the year before the election takes effect. For mark-to-market treatment in 2026, the election needed to be filed with the 2025 return. New taxpayers who weren’t required to file a prior-year return have until two months and 15 days after the first day of the election year. There is no retroactive election. Missing the deadline means waiting a full year.9Internal Revenue Service. Topic No. 429, Traders in Securities
Whichever tax treatment applies, accurate record-keeping is non-negotiable. Each leg must be documented separately, with entry and exit prices, dates, and associated carrying costs. The IRS expects the futures and cash positions tracked independently, even though you’re managing them as a single strategy. Getting this wrong doesn’t just mean an incorrect return. It can mean deferred losses you didn’t anticipate, constructive sale gains you didn’t budget for, or capitalized carrying costs that reduce your basis in ways that surface years later when the position finally closes.