The geometry
Front-spread / ratio: more short options than long, typically 1×2. You reduce debit or even take a credit. Beyond the short strikes the extra short option is economically naked. Backspread: more long options than short — you pay (or receive a small credit) for convexity in the tail and you lose if spot pins near the short strike.
Always draw payoff at expiry and T+0. Risk lab is for that drawing, not for fills.
When desks consider them (mechanics)
Call ratios sometimes appear when a trader is moderately bullish but thinks a melt-up is unlikely — they are selling the far tail. Put ratios appear when moderately bearish with disbelief in a crash. Those beliefs are often wrong in crypto.
Backspreads appear when implied tails look cheap versus a crash or squeeze scenario. They still bleed theta if nothing happens.
Margin and liquidation
Venues may margin a ratio like a naked short plus a long. That can wipe a portfolio in a squeeze even if the “story” was a small credit. If you cannot explain the margin to yourself, do not use the ratio.
Defined-risk verticals exist precisely so you can skip this class of structure until you need it.
Greeks intuition
Near the short cluster, short gamma can be violent. Far in the long-backspread tail, long gamma dominates. Vanna/volga matter if you are using them as a vol-tail expression.
See greeks and vanna-volga guides.
Execution
Combo the ratio if the venue allows. Legging a 1×2 in a fast tape is how you get the shorts without the long. Liquidity on the extra wing is often worse.
Match: only some venues advertise combo/RFQ quality. Check /venue profiles and /venue/best-for/api-traders if that is your constraint.
Practice this on OptionsMatch
Build 1 long / 2 short in /t/btc/strategy and look at the unrestricted side. Compare to a vanilla vertical. Education — not a recommendation to sell ratios.
Advanced structure. Undefined risk is real.