Ratio put spread
A systematic options approach—Ratio put spread—defined by explicit rules, testable on history, and fragile when costs or regimes change.
Overview
This strategy consists of a short position in NS close to ATM put options with a strike price K1, and a long position in NL ITM put options with a strike price K2, where NL < NS. Typically, NL = 1 and NS = 2, or NL = 2 and NS = 3.
Ratio put spread sits in the Options chapter of the systematic catalog. On QUSXFI we treat it as a testable hypothesis: specify entries, exits, sizing, and costs—then ask whether edge survives out-of-sample scrutiny.
Discretionary traders often arrive at similar ideas intuitively; the quantitative version forces you to write the rule before you see the next bar. That discipline is what makes results reproducible—or exposes them as luck.
Based on the research catalog 151 Trading Strategies (Kakushadze & Serur, 2018), section 2.39. Educational summary—not a replication of the full formal definition.
How the Strategy Works
Data alignment for Ratio put spread (rolls, corporate actions, holiday calendars, contract specs) is part of the strategy, not housekeeping.
In Options, microstructure around opens, rolls, and fixes can dominate small statistical edges on Ratio put spread.
Implementation and Research Process
For §2.39 Ratio put spread, write the rule set so another researcher could replicate without you in the room.
Log regime tags beside Ratio put spread performance slices—vol level, rate cycle, liquidity stress.
Archive Ratio put spread failure modes with dates—research firms learn from documented breaks, not from erased losing months.
Risk: What Breaks This Strategy
Ratio spreads in Ratio put spread leave naked option exposure on one side—defined on paper, open-ended in a trend.
Volatility and spot move together in shocks; the ratio that looked balanced at entry can be lopsided within minutes.
Gamma near short strikes accelerates losses faster than linear payoff diagrams suggest.
Common Mistakes to Avoid
- Changing Ratio put spread parameters after each losing week—implicit discretion destroys reproducibility.
- Using academic §2.39 definitions for Ratio put spread while ignoring borrow, margin, or contract specs.
- Stacking Ratio put spread with correlated sidebar strategies without netting exposures.
- Confusing this educational Ratio put spread summary with compliance-approved investment advice.
How to Study This Strategy
- Compare Ratio put spread to one sidebar alternative net of costs—document why you chose this structure.
- Add conservative costs to Ratio put spread; rerun with 2× spreads and compare drawdown paths.
- Restate Ratio put spread (§2.39) as numbered rules another researcher could implement cold.
- Run a paper book on Ratio put spread for a full signal cycle; export trades and tag regimes manually.
- Write a one-page Ratio put spread failure memo: three break modes and early warning signs.
Key Takeaways
- Ratio put spread in Options is a testable rule set—a systematic options approach—ratio put spread—defined by explicit rules, testable on history, and fragile when costs or regimes change.
- Translate every clause of Ratio put spread into code or a checklist; judgment steps are not yet quantitative.
- Costs widen when Ratio put spread signals fire most aggressively—stress at 2× baseline spreads.
- Changing Ratio put spread parameters after each losing week—implicit discretion destroys reproducibility.
- Ratio spreads in Ratio put spread leave naked option exposure on one side—defined on paper, open-ended in a trend.
Learning Tip
Explain Ratio put spread to someone who only knows Basic Trading charts—if you need unexplained jargon, the spec is not ready.
Explore related strategies in the sidebar or return to the full catalog.