The spreads so far were balanced, one leg against one leg. A ratio spread is unbalanced: buy one option and sell two further out. A backspread is the reverse: sell one and buy two. The imbalance is the point. Both take a view on direction and on volatility at the same time.
The 1x2 call ratio
Stock at $100. Buy one $100 call at $4.00 and sell two $110 calls at $1.60 each. You pay $4.00 and collect $3.20, a net debit of $0.80. If the stock finishes below $100 everything expires worthless and you lose the $0.80. At $110 the bought call is worth $10 and the sold calls are worthless, so you make $10 minus $0.80, which is $9.20. That is the maximum. Above $110 the two short calls gain against you twice as fast as the long call gains for you, so profit falls one dollar per dollar. At $119.20 it is back to zero. Above that the losses have no ceiling. The picture is a peak at the short strike, sloping down without end to the right.
Buy one $100 call, sell two $110 calls, 30 days out. Profit peaks at $110 at expiry and falls without limit above the upper breakeven. Raise volatility and watch the right side drop before expiry.
Drag the volatility slider up and watch the green line: the whole right side drops, because two short options gain value faster than the one you own. Drag days toward zero and the peak at $110 rises into place. The ratio earns its money late, from a slow drift that ends near the short strike.
Traders often set the strikes so the trade is done for zero or a small credit. Then there is nothing to lose on a fall and a whole zone of profit above the long strike. The view it expresses: mildly bullish, expecting a drift up toward the short strike but not an explosion, and a belief that the upper options are rich.
The naked leg
One of the two short calls is covered by the long call. The other is not. That is the naked leg, and it is what gives the ratio spread its unlimited risk. Above the short strike the position behaves exactly like a short call. A gap up through $110 on news is the scenario that hurts, and volatility rising at the same time makes the mark-to-market worse before expiration even arrives. Brokers margin a ratio spread on that naked leg. It is not a defined-risk trade, whatever the small debit suggests.
The Greeks change with the stock
A ratio spread is not simply long or short volatility; it depends where the stock is. Near the long strike and below it, the one long option is the closest to the money and it dominates: the position is slightly long gamma and long vega. As the stock climbs toward the short strike, the two short options take over, and by the short strike the position is heavily short gamma and short vega. So the same trade that was mildly long volatility at entry becomes strongly short it exactly when the stock rallies toward the danger zone.
Slightly positive at and below the $100 long strike, deeply negative around the $110 short strike. Switch Greeks: gamma follows vega, and theta turns positive where the short options dominate.
That shift is the practical danger. A trader who put on a 1x2 as a gentle bullish bet can find, after a rally, that they are running a large short volatility position with a naked call attached.
The backspread
Flip the ratio and you have the backspread: sell one $100 call, buy two $110 calls, usually for a credit. Below $100 you keep the credit. The worst case is the stock exactly at $110 at expiration, where the short call is worth $10 and both long calls are worth nothing. Above $110 the two long calls pull ahead and profit is unlimited. So a backspread is the position for "this could rip, and if it does not I want to keep something". Its Greeks are the mirror image of the ratio: long gamma and long vega once the stock heads toward the long strikes. Its cost is the valley at the long strike, which is exactly where a slow drift would leave you.
Sell one $100 call, buy two $110 calls. The worst place to finish is $110. Raise volatility and the whole green line lifts: the backspread is long vega.
Put versions mirror all of this on the downside. A put ratio spread sells the crash; a put backspread buys it. Because puts below the market carry higher implied volatility than calls above it on most stocks, put ratios collect more and put backspreads cost more.
| 1x2 ratio | 1x2 backspread | |
|---|---|---|
| Legs | Buy 1, sell 2 | Sell 1, buy 2 |
| Vol view | Short vega and gamma toward the short strike | Long vega and gamma toward the long strikes |
| Best case | Stock at the short strike | Big move through the long strike |
| Worst case | Unlimited past the short strike | Stock at the long strike |
The maths: breakevens for ratios and backspreads
1x2 call ratio, long strike K1, short strike K2, width w = K2 - K1. If done for a debit D: lower breakeven K1 + D, maximum profit w - D at K2, upper breakeven K2 + (w - D). If done for a credit C: no lower breakeven, maximum profit w + C at K2, upper breakeven K2 + w + C. Above the upper breakeven the loss grows by $1 per $1, the naked call.
1x2 call backspread, short K1, long two at K2, credit C: lower breakeven K1 + C, maximum loss w - C at K2, upper breakeven K2 + (w - C). Worked example: sell the $100 call at $4.00, buy two $110 calls at $1.60, credit $0.80. The lower breakeven is $100.80, the worst case at $110 is $10.00 minus $0.80, a $9.20 loss, and the upper breakeven is $110 + $9.20 = $119.20. It is the same $119.20 as the ratio, because the backspread is exactly the ratio turned upside down.
Your turn
Open NVDA. Find the 25-delta call on the monthly chain, then read the mid of the at-the-money call and the mid of the 25-delta call. Two of the second against one of the first tells you whether your 1x2 is done for a debit or a credit.