A ratio spread is an options strategy that uses an uneven number of contracts at different strikes. The classic build is long one option at one strike and short two at another, all with the same expiry. Traders use it to back a modest move in the underlying and to benefit from time decay on the extra short option.
You can run a ratio with calls or puts. A ratio call spread is mildly bullish up to the short strike. A ratio put spread is mildly bearish down to the short strike. In both cases the risk flips if the underlying runs too far, because the extra short leaves you exposed beyond a second break-even.
How a ratio spread is built
The standard construction is one-by-two, often written 1x2. You buy one near-the-money option, then sell two further out at a different strike. Same underlying, same expiry. The short strike sits above the long for calls and below the long for puts.
- Ratio call spread: buy 1 call at strike A, sell 2 calls at higher strike B.
- Ratio put spread: buy 1 put at strike A, sell 2 puts at lower strike B.
The trade can be opened for a small debit or a net credit. That depends on how far apart the strikes are and the shape of implied volatility. If you collect a credit, the position can profit even if the market drifts the “wrong” way by a small amount. If you pay a debit, you need the underlying to move towards the short strike to overcome the cost.
Traders usually choose the long strike near the current price to keep sensitivity to the directional view, then place the short strike where they think the move may stall. Some push the short strike a little further to reduce the chance of being breached, at the cost of a lower initial credit or a higher debit.
What the payoff looks like at expiry
A ratio spread creates a lopsided payoff. There is a zone where profits are best, centred on the short strike. There is also a second break-even beyond which losses grow because you are net short one option in the wings.
Here is a simple example with a ratio call spread:
- Underlying at entry: 100
- Buy 1 100 call for £5
- Sell 2 110 calls for £2 each, collect £4
- Net cost: £1 debit
At expiry the outcomes look like this:
- If the underlying finishes at or below 100, all options expire worthless and you lose the £1 debit.
- Between 100 and 110, the long call gains value, the shorts are out of the money. Your profit is the intrinsic value of the 100 call minus the £1 debit. That rises linearly and peaks just before 110.
- Exactly at 110, the 100 call is worth £10 and the short 110s have no intrinsic value. Profit is £9, which is the maximum in this example.
- Above 110, the two short calls start to bite. Past the upper break-even, profits turn to losses and downside grows as the price keeps rising. With this setup the second break-even is at 119.
The same idea applies in reverse for a ratio put spread. Your sweet spot is around the short put strike. A deeper drop through that level can turn the position into a growing loss into expiry.
If you establish the trade for a net credit, you may have two break-evens on the profit side and none below the long strike for a call ratio, or above the long strike for a put ratio. The exact points depend on the strikes and net premium. Many traders sketch the payoff or use a calculator before placing the order.
When traders use ratio call and ratio put spreads
Ratio spreads suit views that are directional but limited. You expect a move towards a level, not a runaway trend. Common motivations include:
- Targeting a moderate move to a known resistance or support area to capture the peak at the short strike.
- Taking advantage of rich implied volatility at the chosen short strike to collect extra premium.
- Reducing the cost of a hedge. For example, owning a protective put but paying for it by selling extra puts further below.
- Expressing a view on skew. Equity indices often price puts richer than calls for the same distance from the money, which shapes net credit or debit.
You will see ratio spreads used on single shares, indices, futures and liquid crypto options where listed. Some traders combine them with stock positions, for instance holding shares and running a small ratio call spread above, which behaves like a covered call up to the short strike but then introduces extra short exposure if the rally extends.
Risks, Greeks and margin points to watch
The main risk is the tail. You are net short one option if the underlying pushes beyond the short strikes. That creates theoretically unlimited loss for a ratio call and large loss for a ratio put. The risk is most acute near expiry because gamma is high, so price jumps translate into big changes in P&L.
- Theta (time decay) often works in your favour because you are short more options than you are long.
- Vega exposure is usually negative, so a drop in implied volatility helps. A surge in volatility can hurt.
- Delta starts small and directional in your chosen direction, then flips aggressively once the short strike is breached.
Margin treatment varies by broker and venue. Because the strategy contains a naked short component, the required margin can be significant, and assignment risk exists if American-style options are exercised. Check how your provider models the risk, assignment and early exercise. Platform behaviour and risk controls are not standard across the market.
Variations and simple adjustments
Several related structures come up in practice:
- Backspread, sometimes called a ratio backspread. This flips the sign so you are long more options than you sell, for example sell 1 and buy 2 further out. It benefits from large moves and rising volatility, and has limited risk if structured for a credit.
- Broken-wing butterfly. Add an extra long option beyond the short strike to cap the tail risk created by the ratio. This turns the profile into a skewed butterfly with defined loss limits.
- Calendar ratio. Use different expiries for the long and short legs. This adds a term-structure view and changes the Greek mix. Pricing and risks become more complex.
- Rolling and resizing. If the market drifts towards the short strike too quickly, some traders roll the short strike further away, close one of the shorts, or buy a cheap far strike to limit risk.
It also helps to compare a ratio with a plain vertical spread. A vertical has one long and one short, so risk and reward are both capped. A ratio adds extra income and a higher profit peak around the short strike, but introduces uncapped loss in the tail. That trade-off is the entire point of the strategy and should be sized accordingly.
Placing and managing the trade day to day
On an option chain, a one-by-two is normally entered as a single multi-leg order so the prices are linked. Many traders target a small credit or a near-zero cost to reduce downside if the view is wrong. Once in the position, they watch:
- Distance to the short strike, especially as expiry approaches.
- Implied volatility at both strikes, since a shift in skew can move the mark-to-market.
- Assignment risk if one of the short legs goes in the money and the options allow early exercise.
Adjustments are part of the playbook. If the underlying races through the short strike, you can close the spread, add a protective long farther out, or roll everything to a later expiry. None of these moves is free, so many users pre-define a tripwire price or P&L at which they will cut or change the trade.
Used with care, a ratio spread is a neat way to express a bounded view while using premium from the extra short to fund or boost the position. The price for that extra carry is tail risk, which is why strikes, size and exit rules matter more here than in a conventional vertical.