VIX Term Structure Roll (Contango Carry)

Overview

Spot VIX is a number, not something you can buy. What you can trade are VIX futures, which are bets on where VIX will be at a future date. And here is the structural fact the entire strategy rests on: most of the time, VIX futures trade above spot VIX. The curve slopes upward. That is called contango.

Why? Because people want protection against future volatility spikes, and they are willing to pay up for it. The future price embeds a premium for uncertainty that, on average, does not materialise.

If futures are above spot and, at expiry, the future must converge to spot, then a short position in the future earns the difference as the contract ages. That is roll yield, or carry. Sell the front future, wait, let it drift down toward spot, buy it back cheaper. Repeat.

This works. It works consistently. It has also, more than once, destroyed everyone doing it in the space of a single afternoon.

Strategy logic

• The curve check: Every day, compare the front VIX future to spot VIX and to the second-month future. If the front is meaningfully above spot and the second is above the front, the curve is in contango and carry is positive.
• The position: Short the front-month future, or hold a short position in a constant-maturity blend of the first and second contracts so you are not exposed to a single expiry date.
• The roll: As expiry approaches, shift the position out to the next contract. This is where the carry is actually harvested.
• The exit: When the curve inverts into backwardation, meaning the front future is trading below spot VIX, the carry has turned negative and the market is pricing near-term stress. Get out.

That last rule is not optional. Backwardation is the market telling you that the thing you are short is now in demand. Traders who overrode it in February 2018 did not get a second chance.

Parameters (knobs)

• Contango threshold: Requiring more than a small slope before going short filters out the ambiguous days. A threshold of a few percent between contracts one and two is a common starting point.
• Instrument choice: Futures give you control and your own margin. ETPs are easier to access but have their own daily rebalancing mechanics, and a leveraged short-vol ETP can be forced to buy futures into a spike, which is precisely the feedback loop that blew up in 2018.
• Position size: The single most important parameter, by a wide margin. VIX is not a normal asset. A one-day move of plus 100 percent is inside the realistic distribution.
• Hedge spend: How much of the carry you give back buying far out of the money VIX calls. Spending a meaningful slice of the premium on a hedge turns an unsurvivable strategy into a survivable one.

Where it works and where it hurts

Contango is present roughly three quarters to four fifths of the time. In those periods the carry is steady and pleasant. The equity curve rises smoothly. It is genuinely one of the most reliable-looking return streams in all of finance, which is precisely why it is dangerous.

The failure is total and fast. VIX does not decline gently and then spike gently. It sits at 12 for months, then goes to 30 in a day and 50 in a week. A short front-month future in that move loses a multiple of the entire premium you spent a year collecting. On 5 February 2018, one popular inverse volatility product lost more than 90 percent of its value in a single after-hours session and was terminated. The people holding it had been earning that steady, pleasant carry for years.

This strategy can and will lose several years of gains in a matter of days. That is not a risk warning bolted on for compliance. It is the defining characteristic of the trade, and any presentation of it that buries this is misleading you.

Backtest design checklist

• Use settlement prices from the actual futures, not a reconstructed index. Volatility ETP index histories are back-filled and flattering.
• Model the roll cost. VIX futures spreads widen exactly when you most want to trade.
• Simulate margin. Exchange margin on VIX futures rises sharply in a spike. Confirm your capital survives, because a margin call at the peak means you realise the maximum possible loss.
• Do not allow intraday stop fills at your chosen price. VIX gaps. Assume you get filled far worse than your stop.
• Test the exit rule's lag. If you flatten on a backwardation signal computed at the close, you are already one full day into the move. Measure how much that costs.
• Include the tail hedge in the base case, not as an optional add-on. Without it, the honest backtest ends at zero.

Common failure modes

• Sizing off the average and not the tail. The average daily move in VIX futures tells you nothing useful about a strategy whose whole risk lives in the extreme.
• Overriding the backwardation exit. It always feels like an overreaction on the day. It is not.
• Leveraged ETPs. Their forced daily rebalancing means they buy volatility as volatility rises, amplifying the very move that is hurting you. Never use a leveraged short-vol product as the expression of this trade.
• Treating a great Sharpe ratio as evidence of quality. Short volatility carry has a spectacular Sharpe ratio right up until it does not. The Sharpe ratio is the wrong measurement tool for a return distribution with this shape.

Our notes and suggestions

We would rather see someone express this as a small, hedged, rules-driven sleeve than as a core position. Buy the far out of the money VIX calls. Honour the backwardation exit without discussion. Size it so that a VIX move from 13 to 50 is a bad quarter and not a career-ending event.

And be entirely honest with yourself about the marketing around this. Short-volatility carry is packaged and sold constantly, always with a smooth backtest attached, and the smoothness is the product of a distribution that saves all of its bad news for one day. What would change our mind: persistent backwardation, or a structural shift where the volatility risk premium is no longer paid because too much capital is chasing it.