Tailing the Hedge

A tailed hedge is a futures position that is slightly smaller than the underlying exposure it protects, adjusted downward to compensate for daily mark-to-market cash flows earned during the holding period. Because futures contracts settle daily while forward contracts settle at maturity, a futures hedge accumulates interest on cash gained or lost each day—money that reduces the net size of the position needed to achieve the same final payoff.

Why daily settlement creates this problem

When you enter a futures contract, the exchange demands settlement of daily price moves. If the futures price rises, you receive cash immediately; if it falls, you pay. This daily cash flow is fundamentally different from a forward contract, which settles all gains or losses in one lump sum at maturity.

A company hedging a future purchase with futures will receive cash each day the price falls in its favour. That cash earns interest—whether reinvested at LIBOR, the risk-free rate, or the company’s own cost of capital. Over weeks or months, this interest accumulates to a material amount.

The result: you need fewer futures contracts to achieve the same economic hedge as a forward would provide.

The arithmetic of tailing

Suppose you plan to buy 1 million barrels of crude oil in 90 days. A crude oil futures contract controls 1,000 barrels. Naively, you might short 1,000 contracts as a perfect hedge.

But your daily gains will earn interest. If the interest rate is 5 per cent per annum—roughly 1.25 per cent over 90 days—then the present value of your position 90 days from now is worth about 1.25 per cent less than its face value today. To achieve the same protection, you should buy only 987 or 988 contracts instead, and let the daily interest accumulation make up the difference.

More formally:

Number of futures = (Notional exposure × Discount factor) / Contract size

where the discount factor reflects the interest rate and time to maturity. As rates rise or time extends, the tail becomes larger and you short progressively fewer contracts.

When to tail and when to ignore it

For overnight hedges or short-dated positions, tailing is negligible. If you’re hedging three weeks of inventory turnover, the interest effect is pounds, not thousands.

But institutional asset managers, pension funds, and corporate treasury departments routinely tail. A monthly or quarterly hedge that accounts for tailing can reduce operational costs by 1–2 per cent of the hedged amount. In a portfolio of billions, that is material.

Tailing also matters in dynamic hedging strategies where positions are rebalanced frequently. Each rebalancing implicitly generates cash that must be reinvested, and failing to account for it introduces a subtle drift in the hedge ratio.

The cost and benefit trade-off

Tailing is defensive—it prevents you from over-hedging and accidentally creating a short bias. A tailed hedge protects against the scenario where daily cash gains compound so substantially that your effective short position grows larger than intended, leaving you exposed to prices moving in the unfavourable direction.

The drawback is administrative friction. Calculating the exact discount factor requires knowing your funding rate precisely, and recalculating it as rates shift means continuously adjusting contract counts. Some firms accept a small amount of over-hedging (holding full notional futures) to avoid this overhead.

For leveraged or prime brokerage setups, where every basis point of return is tracked, tailing is standard. For smaller hedges or volatile rate environments where recalculation becomes expensive, a simpler approach—holding the full notional and accepting the rounding—is common.

Relationship to other hedging mechanics

Tailing sits between two extremes. On one end is a perfect forward contract, which requires zero adjustment because there is no daily settlement. On the other is a naive futures contract hedge of exactly the same notional size, which slightly over-hedges because of reinvested cash.

The concept also connects to repo financing. If you’re financing a hedge via a repo loan, your borrowing cost is your funding rate, and tailing accounts for this automatically. In a falling-rate environment, your daily cash gains compound at a higher rate, so tailing requires an even smaller hedge.

See also