Put-Skew Steepeners and Flatteners

A single risk reversal captures put skew at one expiry, on one day. But put skew is not one number — it exists at every expiry, and the steepness (how much more expensive puts are than calls, per unit of distance from the money) often differs meaningfully between, say, one-month and one-year options. A trader who has a view not on skew's level but on how that steepness itself will evolve over time is trading a different, second-order object entirely.

A put-skew steepener bets that near-term skew will get steeper relative to longer-dated skew (or vice versa for a flattener), typically built by combining risk reversals at two different expiries rather than trading a single expiry's skew outright.

Why near-term and long-term skew diverge

Near-term skew tends to react sharply to immediate, event-driven fears — an upcoming central bank decision, a binary political outcome, an earnings cluster — because those events sit inside the near-term expiry's window and nowhere near the far one. Long-term skew moves more slowly, reflecting structural demand for tail protection (pension funds hedging years out) that doesn't spike and fade with a single week's headlines. A steepener trade is a bet that near-term event risk gets priced up faster, or fades faster, than the long-term structural skew around it.

Worked example

Ahead of a widely anticipated central bank decision, the one-month risk reversal (25-delta put minus 25-delta call implied vol) is trading at 6 points, unusually steep versus its typical 3-point level, because traders are bidding up near-term puts for protection. The six-month risk reversal, less exposed to a single month's event, is trading at a more normal 4 points.

A trader believing the near-term steepness overshoots puts on a flattener: sell the rich one-month put-skew (sell puts, buy calls in the near-term risk reversal) while buying the relatively cheaper six-month skew (buy puts, sell calls there), sized to be roughly neutral to the underlying's direction and to the overall level of volatility. If, after the event passes without a major surprise, the one-month risk reversal falls back to 3 points while the six-month is little changed, the near-term leg — sold rich — gains more than the long-term leg loses, and the trade profits from the term structure of skew normalizing, independent of which way the underlying actually moved on the news.

What this means in practice

Skew term-structure trades are a step further removed from simple directional or even single-expiry volatility trades — they require a view on how an already second-order quantity (skew) itself evolves through time, and are correspondingly more of a relative-value, desk-level trade than something built into most retail strategies. They matter in practice around known event risk, since options desks routinely see near-term skew steepen mechanically ahead of earnings, elections, and central bank meetings, then flatten back once the event passes, whether or not the event itself was surprising.