Diagonal put spread
A systematic options approach—Diagonal put spread—defined by explicit rules, testable on history, and fragile when costs or regimes change.
Overview
This is a diagonal spread consisting of a long position in a deep ITM put option with a strike price K1 and TTM T′, and a short position in an OTM put option with a strike price K2 and shorter TTM T < T′.
Diagonal 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 2.21. Educational summary—not a replication of the full formal definition.
Term-Structure Logic
Diagonal put spread trades calendar or diagonal structure—theta and term-structure moves dominate direction in calm tapes.
Before backtesting Diagonal put spread, write the economic hypothesis in one sentence a risk manager would accept or reject.
Implementation and Research Process
For Diagonal put spread, align front and back expiries to your event calendar—macro prints in the front month rewrite term structure.
For §2.21 Diagonal put spread, write the rule set so another researcher could replicate without you in the room.
Log regime tags beside Diagonal put spread performance slices—vol level, rate cycle, liquidity stress.
Risk: What Breaks This Strategy
Diagonal put spread separates calendar risk from direction, but front-month vol shocks can hurt both legs if the term structure inverts violently.
Rolls around events can invert the edge you backtested on smooth historical surfaces.
Theta harvest can look stable until a single name event gaps through both expiries.
Common Mistakes to Avoid
- Running Diagonal put spread through front-month events without a blackout calendar.
- Using academic §2.21 definitions for Diagonal put spread while ignoring borrow, margin, or contract specs.
- Changing Diagonal put spread parameters after each losing week—implicit discretion destroys reproducibility.
- Confusing this educational Diagonal put spread summary with compliance-approved investment advice.
How to Study This Strategy
- Write a one-page Diagonal put spread failure memo: three break modes and early warning signs.
- Map Diagonal put spread to Basic Trading chart concepts you will use as filters—not as substitutes for rules.
- Run a paper book on Diagonal put spread for a full signal cycle; export trades and tag regimes manually.
- Compare Diagonal put spread to one sidebar alternative net of costs—document why you chose this structure.
- List every data field Diagonal put spread needs in Options; verify point-in-time integrity.
Key Takeaways
- Diagonal put spread isolates term-structure and theta from raw direction—until front-month events invert the curve you modeled.
- Roll cadence on Diagonal put spread must specify event blackouts; earnings in the front leg rewrite the thesis.
- Calendar spreads lose when front vol explodes faster than back vol catches up.
- Theta harvest on calendars can look stable until one gap through both expiries.
- Compare Diagonal put spread to outright vol trades in the sidebar—time spread is not a free vol-neutral lunch.
Learning Tip
Explain Diagonal 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.