Part XIII · Discipline · Chapter 13E

Worked examples: the portfolio

Ten portfolio decisions, reasoned end to end

Where we are

Chapters 10A to 10I took the edges one at a time. Chapters 13A to 13C then built the tools for judging them: the retail haircut, the conviction score, and the pipeline from a signal to a sized trade. Chapter 13D used those tools on ten swing trades. This chapter applies them to ten decisions about a whole portfolio, from a pitched Sharpe ratio to the size of a put-writing sleeve.

What you need first
  • The Sharpe ratio, its 30% to 50% haircut for the skew of short volatility, and the stress scenarios S1 to S3 (Chapter 1D).
  • Drawdown, leverage, margin and path dependency (Chapter 1E).
  • The five categories of edge (Chapter 10A), and the edges themselves in Chapters 10C to 10I: the variance risk premium, trend following, the calendar overlays, the regime filters and the rejected strategies.
  • The retail haircut (Chapter 13A), the conviction score and its thresholds (Chapter 13B), and sizing from a loss budget (Chapter 13C).
  • Delta, gamma and vega (Chapter 5C), and the tax treatment of Section 1256 contracts (Chapter 2E).

1 · How to read the examples

The Edge Book, the source of this chapter, calls it the most important in the book, because worked examples show the full reasoning path and not just the conclusion. Each one here walks through the actual arithmetic of a decision: distributions, Greeks, margin, the conviction score and the kill rule. By the end you should be able to apply the same chain to any new strategy you meet.

Every example follows the same template, opening with the question, a specific operational decision, and the setup, the numbers that bear on it. The walkthrough then builds the reasoning chain step by step. The conclusion gives a sized position or a rejection, and what it teaches draws out the principle that carries over to other decisions. Do not skim these, since the point is the granular reasoning, and a verdict without its reasons cannot be reused.

In plain terms

Each example asks the same short list of questions in the same order. How good is the claim once the usual haircuts are taken off? Do the regime filters allow the trade today, and what would it lose in a crash? How does it score on evidence, mechanism, regime, execution and sizing, and how many contracts does the loss budget allow? A trade that clears every question gets capital. Most do not, and seeing where each one fails is the lesson.

Two formulas from earlier chapters carry most of the arithmetic. The first is the conviction score of Chapter 13B, which multiplies five scores, each between 0 and 1. The factor EE scores the quality of the evidence and MM the clarity of the mechanism. The factor RR scores how well the current regime suits the trade, XX how feasible the execution is, and SS how survivable the sizing is.

C=E×M×R×X×S C = E \times M \times R \times X \times S (13E.1)

Chapter 13B reads the product against two thresholds. A score of 0.5 or more is high conviction, so allocate. From 0.3 up to 0.5 is medium conviction, which calls for a small allocation or a test size. Below 0.3 the conviction is insufficient, so do not trade. Because the score is a product, one weak factor drags it down however strong the others are. Five factors of 0.9 give 0.95=0.590.9^5 = 0.59, while four of 0.9 and one of 0.3 give 0.94×0.3=0.200.9^4 \times 0.3 = 0.20.

Why one weak factor sinks the product

Take the natural logarithm of both sides of (13E.1). A logarithm turns a product into a sum (Chapter 1A):

ln⁡C=ln⁡E+ln⁡M+ln⁡R+ln⁡X+ln⁡S \begin{aligned} \ln C &= \ln E + \ln M + \ln R \\ &\quad + \ln X + \ln S \end{aligned} (13E.2)

Each factor below 1 has a negative logarithm, so each one subtracts a penalty from the total. A factor of 0.9 costs ln⁡0.9=−0.105\ln 0.9 = -0.105, while a factor of 0.3 costs ln⁡0.3=−1.20\ln 0.3 = -1.20, more than eleven times as much.

The thresholds become budgets in the same units. High conviction, C≥0.5C \ge 0.5, means the penalties sum to no more than −ln⁡0.5=0.69-\ln 0.5 = 0.69, and medium conviction, C≥0.3C \ge 0.3, allows 1.20 in all. So a single factor of 0.3 spends the entire budget for medium conviction by itself, and four perfect scores could not buy it back.

The second formula sizes a position from an explicit loss budget, and Example 10 derives it with numbers. Several examples also price a position in the stress scenarios of Chapter 1D, which this chapter uses throughout:

ScenarioSPXVIX
S1, mildDown 10%Up 10 points
S2, moderateDown 20%Up 25 points
S3, severeDown 35%Up 50 points

2 · Example 1: the Sharpe trap

The question. A friend pitches you a strategy: "It's a short-vol strategy with a Sharpe ratio of 0.85 over 10 years. Better than SPX." Should you allocate?

The setup. The strategy sells far out-of-the-money (OTM) SPX puts systematically, and its backtest runs from 2014 to 2023. The pitch quotes an annual return of 11% at a volatility of 13%, which is where its 0.85 comes from: 11/13=0.8511/13 = 0.85, with no risk-free rate taken out.

Worked example: Haircutting a pitched Sharpe ratio

Step 1: haircut for skew. Far-OTM puts have a skewness well below −3.0, while the CBOE PUT Index, which sells at-the-money (ATM) puts, has −2.09 (Chapter 1D). Chapter 1D's rule cuts the Sharpe ratio of any short volatility strategy by 30% to 50% for that skew. At a cut of 35%, near the lenient end, the pitch becomes 0.85×0.65=0.550.85 \times 0.65 = 0.55, its skew-adjusted equivalent.

Step 2: haircut for implementation. A live retail account typically keeps 0.6 to 0.7 times an academic-style number like this one (Chapter 13A), which at 0.65 gives 0.55×0.65=0.360.55 \times 0.65 = 0.36.

Step 3: check the backtest period. The years from 2014 to 2023 include very few stress events: one quick spike in March 2020 and no extended bear market. The data do not reflect the full distribution of regimes, and a short volatility Sharpe ratio built on a benign decade is unreliable.

Step 4: project the tails. Far-OTM puts carry asymmetric exposure to a crash, and a rough mental stress test of the sleeve gives the losses in the table.

ScenarioEstimated sleeve loss
S1: SPX down 10%, VIX up 108% to 15%
S2: SPX down 20%, VIX up 2525% to 40%
S3: SPX down 35%, VIX up 5055% to 85%

The strategy has been tested in none of these, so the backtest is silent on its real tail behavior.

Step 5: compare with the simpler alternative. Over the same years SPX returned about 12% a year at a volatility of about 16%, with full liquidity, efficient taxes and known tail behavior. Its Sharpe ratio of about 0.65 implies that a risk-free rate of about 1.6% was taken out. On the pitch's basis, with none taken out, it is 12/16=0.7512/16 = 0.75. After the haircuts, the candidate's realistic 0.36 is materially worse than simply holding SPX, at about 0.5 once SPX is adjusted for retail frictions.

Step 6: score the conviction. Every factor is weak, and sizing and evidence are the weakest:

FactorScoreWhy
Evidence EE0.30The backtest covers a benign period only
Mechanism MM0.50Writing far-OTM puts earns a real premium for catastrophic risk, harvested only with patience
Regime RR0.40The strategy assumes that a calm regime continues
Execution XX0.55Far-OTM SPX options have wider bid-ask spreads
Sizing SS0.30The tail loss is 2 to 5 times the premium, and survivability is unclear without more data

The product is C=0.30×0.50×0.40×0.55×0.30=0.010C = 0.30 \times 0.50 \times 0.40 \times 0.55 \times 0.30 = 0.010, far below the threshold of 0.3.

Conclusion. Do not allocate, because the pitch misleads in three ways: it ignores skew, it applies no retail haircut, and its backtest contains no real stress. After the conviction analysis, the strategy does not pass admission.

What it teaches

Pitched Sharpe ratios are paper Sharpe ratios: the translation from "0.85 in a 10-year backtest" to a realistic expectation in a retail account is roughly 0.36, a discount of 1−0.36/0.85=58%1 - 0.36/0.85 = 58\%. This is the typical haircut for short volatility strategies, and the gap is systematic, not pessimistic.

Familiar ground

A short volatility backtest from 2014 to 2023 is like a safety analysis from a trial that enrolled almost no high-risk patients. Its adverse event rate is accurate for the patients it saw and silent about the ones who matter. The spectrum of the sample decides what it can tell you. One brief spike in March 2020 is a thin spectrum for a strategy whose risk lives in the tail.

3 · Example 2: VRP harvest at $1 million in a calm regime

The question. You have a $1 million portfolio and want to add a harvest of the variance risk premium (VRP). The VIX is at 14, the term structure is in contango with the VIX divided by the VIX3M at 0.85, and 21-day realized volatility is 12%. How much should you add, and how?

The setup. You are considering a 15% allocation to cash-secured puts on XSP, at the money with one month to expiry and sold each month. The goal is to capture the index VRP.

Worked example: Sizing and stress-testing a put-writing sleeve

Step 1: choose the variant. Of the put-writing variants in Chapter 10C, ATM monthly cash-secured XSP puts come closest to the academic VRP with a reasonable retail implementation. This is what the book calls the VRP harvest. Holding the strike in cash eliminates margin risk, and XSP options are Section 1256 contracts, taxed 60% as long-term gains (Chapter 2E).

Step 2: size the position. Fifteen percent of $1 million is $150,000 of notional, against 600×100=$60,000600 \times 100 = \$60{,}000 for each contract with XSP at 600. Each put is fully cash-secured at its strike, so each ties up about $60,000 of cash. The allocation is therefore 150,000/60,000=2.5150{,}000/60{,}000 = 2.5 contracts: 2 or 3, with $120,000 to $180,000 of collateral.

Step 3: project a typical month. An ATM monthly XSP put sells for roughly 2% to 3% of the strike, $12 to $18. Three contracts collect $36 to $54 of premium a month in index points, or $3,600 to $5,400 in dollars. That is 0.36% to 0.54% of the portfolio a month, and twelve months of it make 4.3% to 6.5% a year, gross.

Check the rule of thumb with the at-the-money approximation of Chapter 10C, which prices the put at about 0.4 σT0.4\,\sigma\sqrt{T} of the strike. Here σ\sigma is the implied volatility and TT the time to expiry in years. At a VIX of 14 and one month, that is 0.4×0.14×0.289=1.6%0.4 \times 0.14 \times 0.289 = 1.6\%, about $9.70 on a strike of 600. A premium of 2% to 3% fits a VIX of about 17 to 26, so this example's premiums are generous for a VIX of 14.

Premium is not profit either, because in the months when the index falls through the strike the puts pay much of it back. After those losses and the retail haircuts, the Edge Book's realistic net contribution is 2% to 4% a year, and Card 02 in Chapter 13F puts it at 3% to 5%. Read either as a return on the collateral. On $180,000, 2% to 4% is $3,600 to $7,200 a year, about 0.4% to 0.7% of the portfolio. As 2% to 4% of the whole $1 million, it would need the sleeve to earn 11% to 22% a year on its collateral, far above the PUT index's compound return of 9.54% (Chapter 10C).

Step 4: stress-test it. Each put is struck at 600, so in a stress it is worth at least its intrinsic value, the strike minus the index level. Your loss is that value less the premium you took in, times 100:

ScenarioXSPIntrinsic valueLoss per contractThree contractsShare of $1 million
S1540$60$4,200 to $4,800$12,600 to $14,4001.3% to 1.4%
S2480$120$10,200 to $12,000$30,600 to $36,0003.1% to 3.6%
S3390$210$19,200 to $20,000$57,600 to $60,0005.8% to 6.0%

The low end of each row takes the $18 premium and no time value. The top of the S2 and S3 rows allows for the time value that a higher VIX adds, up to the Edge Book's own estimates of $12,000 and $20,000 a contract. The Edge Book's estimates start lower, at about $3,000 in S1, $8,000 in S2 and $15,000 in S3, which all fall below this floor.

A first-order estimate explains the S1 figure: the put's delta of about −0.5 times the $60 fall gives 0.5×60×100=$3,0000.5 \times 60 \times 100 = \$3{,}000 a contract, or $9,000 for three. That estimate ignores gamma, which pushes the put's delta toward −1 as the index falls through the strike (Chapter 5C). For a fall this large, the first-order estimate misses about a third of the loss.

The puts are cash-secured, so there is no margin breach and no forced liquidation. The maximum loss is bounded by the collateral, $180,000 for three contracts, which would need the index to go to zero, and an index does not do that.

Step 5: score the conviction. The table scores the strategy in each of the five domains, where it is strong throughout:

FactorScoreWhy
Evidence EE0.85T1 evidence, from Bondarenko and from Carr and Wu (Chapter 10C)
Mechanism MM0.90A risk premium with a clear mechanism
Regime RR0.85A calm regime in contango
Execution XX0.90XSP is liquid
Sizing SS0.85Cash-securing eliminates the path risk of margin

The product is C=0.85×0.90×0.85×0.90×0.85=0.497C = 0.85 \times 0.90 \times 0.85 \times 0.90 \times 0.85 = 0.497, just under 0.5, so it is formally medium conviction. The Edge Book rounds it to 0.50, reads it as high conviction and allocates.

Conclusion. Sell 2 to 3 contracts of XSP ATM monthly puts, cash-secured. The expected monthly premium is $36 to $54 in index points for three contracts, and the worst monthly mark in S3 is about 6% of the portfolio. The kill criterion is to halt new sales when VIX/VIX3M stays above 1.05 for 3 days. The full phased filter of Chapter 10H starts earlier, halting new entries above 1.00, and Card 02 in Chapter 13F uses that version.

What it teaches

The conviction framework formalizes intuition. Each domain scores 0.85 to 0.90 because the strategy is strong in every dimension, and the product of about 0.50 puts it at the line for high conviction. If any single domain were weak, the product would collapse: with S=0.4S = 0.4 for an oversized sleeve, it falls to 0.85×0.90×0.85×0.90×0.4=0.230.85 \times 0.90 \times 0.85 \times 0.90 \times 0.4 = 0.23, below 0.30.

The figure prices Example 2's puts in each stress three ways. Pick S1 to S3 and compare the floor with the estimate from delta alone: the estimate misses a third of the loss in S1 and nearly half in S3.

$15.00
3
floor loss: $4,500 a contract
with 30 days left: $4,607
delta alone: $3,000 (33% short)
3 contracts: $13,500, 1.4% of $1M

In S1, XSP falls 10% to 540 and the VIX rises 10 points to 24, leaving the put $60 in the money. Delta alone, 0.5 × 60 × 100 = $3,000, misses 33% of the loss at the floor.

Delta alone understates a short put's loss in a large fall. One XSP put, struck at the money at 600 and sold for the premium you set, with the seller's loss a contract drawn at each index level. The floor is its intrinsic value less the premium, what it costs at expiry, and the dashed line is its Black-Scholes value with 30 days left at the stressed VIX (the calm 14 plus the scenario's rise, with no interest rate). The straight line is the first-order estimate from a delta of −0.5, and it falls further behind the floor as the stress deepens from S1 to S3.

4 · Example 3: the same harvest in a stress regime

The question. The same portfolio now faces a VIX of 28, a term structure in backwardation for 5 days with VIX/VIX3M at 1.10, and realized volatility of 32%. With the stress only a day old, should you allocate to the VRP harvest now?

The setup. The portfolio is the same $1 million, with the VIX at 28 and backwardated and realized volatility at 32%. The temptation runs: "The VRP looks elevated. This should be a great time to sell premium."

Worked example: Scoring the harvest in stress

Step 1: check the filters of Chapter 10H. The first filter, VIX/VIX3M above 1.05 for 3 days, has failed, so the kill criterion has triggered. The second, 21-day realized volatility above implied, has failed too. With the VRP negative as well as the curve inverted, both filters say to halt new entries.

Step 2: ask whether a high VIX is a good time to sell. This is the most common retail misconception about the VRP. A high VIX tempts the trader because premiums are richer, but the richer premium comes with five changes:

  • Realized volatility is higher still, at 32% against 28% implied.
  • The distribution of the coming moves is wider than implied volatility prices.
  • Margin expansion under portfolio margin (PM) has already begun.
  • The path of mark-to-market (MTM) losses through this regime is severe.
  • Even cash-secured positions face large drawdowns in their marks.

The rule of 16 (Chapter 5E) turns the gap into days. A VIX of 28 prices a typical day of 28/16=1.75%28/16 = 1.75\%, while realized volatility of 32% delivers days of 32/16=2.0%32/16 = 2.0\%, so the seller is paid for smaller days than the market is producing. The VRP exists when implied volatility exceeds realized. A negative VRP, with realized above implied, is the opposite of the structural premium, and selling premium into it is doing the wrong thing.

Step 3: score the conviction. The evidence and mechanism are unchanged from Example 2, while the other three factors fall:

FactorScoreWhy
Evidence EE0.85The evidence is unchanged
Mechanism MM0.90The mechanism is unchanged
Regime RR0.15The regime is exactly the opposite of supportive
Execution XX0.65Bid-ask spreads are wider
Sizing SS0.35Sizing for survival is much harder when realized volatility exceeds implied

The product is C=0.85×0.90×0.15×0.65×0.35=0.026C = 0.85 \times 0.90 \times 0.15 \times 0.65 \times 0.35 = 0.026, an order of magnitude below the threshold.

Conclusion. Do not enter new positions. For existing positions, reduce the size by 50% by buying back half, or close them entirely if the mark is acceptable, and wait for the filters to normalize before re-entering. This matches the phased filter of Chapter 10H, where a ratio above 1.05 for 3 closes halts all put sales and halves the sleeve. The ratio has not reached the 1.15 that closes non-essential short volatility. And realized volatility of 32% sits just under implied plus 5 points, 33%, the level at which Chapter 10H closes an oversized position outright.

What it teaches

The conviction framework correctly turns off in adverse regimes. The strategy, the evidence and the mechanism are all the same as in Example 2. The collapse of RR alone makes the trade wrong now, even though it is right on average. This is what selectivity looks like in operation. A reviewer of the Edge Book described the successful approach as skipping entire weeks when the criteria were not met: high-conviction trading is mostly not trading.

5 · Example 4: timing a trend allocation

The question. You are considering adding trend following through DBMF, the replication-style fund of Chapter 10D. Trend has been in a multi-year drought, with returns flat to slightly negative in 2023 and 2024. Should you allocate now?

The setup. The portfolio holds 70% equities and 30% bonds, and you want to add trend. DBMF has been flat for 18 months, and the objection is plain: "Trend is broken, so why allocate?"

Worked example: Buying a premium in its drought

Step 1: check the evidence (Chapters 1G and 10D). Hurst, Ooi and Pedersen (2017) cover 140 years of trend following, with every decade positive, and the effect is replicated across many asset classes. Its mechanism combines behavioral under-reaction, compensation for hedgers and the provision of liquidity, which makes the evidence T1.

Step 2: explain the drought. Trend goes through structural droughts in choppy, mean-reverting regimes. The years from 2011 to 2018 were the worst drought in modern history, lasting about 7 years. Trend does not "break": it goes through extended periods in which its signals do not line up across asset classes.

Step 3: weigh the case for waiting. The objection says to wait until trend works again and then allocate, but four facts stand against it:

  • You cannot time the turn of the regime.
  • Trend tends to recover in the same events that hurt other assets, as in 2008, 2020 and 2022.
  • The recovery is fast, so by the time trend "works" you have missed the entry.
  • Allocating during a drought is uncomfortable, but historically it has been a good entry.

Step 4: choose the size and the structure. Allocate 10% to 15% to DBMF, a single vehicle that is transparent and carries lower fees. Build the position over 3 months to avoid the timing risk of a single lump sum. For a $1 million portfolio targeting 12%, that is $120,000 bought as $40,000 a month. Do not try to time the turn of the regime.

Step 5: score the conviction. Four factors are strong, and the regime is the weak one:

FactorScoreWhy
Evidence EE0.90T1, with 140 years of evidence
Mechanism MM0.85A mechanism with several sources
Regime RR0.55A drought regime, not supportive but not adverse
Execution XX0.95DBMF is easy to buy
Sizing SS0.9010% to 15% is well within survivability, and trend has positive skew in a crash

The product is C=0.90×0.85×0.55×0.95×0.90=0.36C = 0.90 \times 0.85 \times 0.55 \times 0.95 \times 0.90 = 0.36, medium conviction, with the regime score as the binding constraint.

Conclusion. Allocate 10% to 15% to DBMF, built over 3 months rather than in one purchase. The medium score says the timing is poor while the structural case is strong. Hold across cycles, and do not exit automatically during droughts. The kill criterion is DBMF's tracking error to the BTOP50, a live index of trend-following funds, above 4% a year for 4 quarters.

What it teaches

Medium conviction, 0.3 to 0.5, means scaling in modestly with an operational adjustment: not zero, and not full size. The regime score caught the drought, and the response is to phase the entry. Chapter 10D sets the limit on that response, since staging spreads the purchase and is not a way of timing trend's cycles.

6 · Example 5: the FOMC even-week overlay

The question. Cieslak and colleagues found the equity premium concentrated in the even weeks of the cycle between meetings of the Federal Open Market Committee (FOMC), as Chapter 10G describes. With a 60% equity allocation, should you reduce equity in the odd weeks?

The setup. The equity allocation is $600,000 of a $1 million portfolio. The idea is to hold 60% in even weeks and 45% in odd weeks, a reduction of (60−45)/60=25%(60 - 45)/60 = 25\%. The vehicle is SPY, held in a taxable account.

Worked example: Pricing a calendar overlay

Step 1: check the evidence (Chapter 10G). Cieslak, Morse and Vissing-Jorgensen (2019) ran their original sample from 1994 to about 2014. The evidence is T2: replicated, but with limited out-of-sample (OOS) data after 2019 and an uncertain hiking cycle in 2022.

Step 2: judge the mechanism. The Fed put and forward guidance give a plausible mechanism. But the effect could decay as the pre-FOMC drift did after 2015 (Chapter 10I), so it stays T2, not T1.

Step 3: count the implementation cost. Rotating SPY in and out of the account, about every 1.5 weeks, costs little in trading and a great deal in tax. The bid-ask spread for SPY is about 0.01%, and slippage is minimal. The cut moves 15 percentage points, $150,000, out and back in each odd week. With about eight meetings a year and three odd weeks in each cycle, that is 24 round trips a year. Crossing a 0.01% spread on $150,000 costs $15 each time, so the year's spread cost is about 24×$15=$36024 \times \$15 = \$360, under 4 bps of the portfolio.

The tax is what matters, because every sale realizes a gain or loss. In a taxable account the rotation is a disaster of tax acceleration: it pays tax now on gains that would otherwise be deferred.

Step 4: frame it by the account. In a tax-deferred account, such as an individual retirement account (IRA) or a 401(k) plan, the implementation cost is small. On cost alone, the rotation there looks worth doing. In a taxable account, the tax acceleration from rotating SPY can cost 20 to 40 bps a year, more than the expected 10 to 30 bps of alpha from the cycle.

Step 5: choose the operational form. Do not rotate the existing SPY position, and use one of three lighter forms instead:

  • Time new contributions and rebalances to start in even weeks.
  • Modulate exposure through the size of a futures position, in ES or the smaller MES. Futures are Section 1256 contracts, taxed 60% as long-term gains whatever the holding period (Chapter 2E).
  • Hold a leveraged ETF on margin during even weeks only.

The lightest implementation of all is to time your discretionary purchases and sales to land in even weeks, with no rotation.

Step 6: score the conviction. Execution is the binding constraint, and it differs by account:

FactorScoreWhy
Evidence EE0.50T2
Mechanism MM0.65A plausible mechanism, with a risk of decay
Regime RR0.65The cycle effect should still be roughly intact
Execution XX0.40 taxable, 0.85 tax-deferredTax acceleration in the taxable account
Sizing SS0.85A modulation of existing exposure, not a new sleeve

The score is C=0.50×0.65×0.65×0.40×0.85=0.072C = 0.50 \times 0.65 \times 0.65 \times 0.40 \times 0.85 = 0.072 in the taxable account and C=0.50×0.65×0.65×0.85×0.85=0.153C = 0.50 \times 0.65 \times 0.65 \times 0.85 \times 0.85 = 0.153 in the tax-deferred one, both below the threshold of 0.3.

Conclusion. Do not run a separate FOMC rotation strategy. In the taxable account, the tax costs more than the cycle is expected to pay. In the tax-deferred account the cost is small, but the score is still half the threshold, because the evidence, the mechanism and the regime are each only moderate. The Edge Book concludes that the expected alpha does not survive implementation at retail scale in either account. Use your awareness of the cycle to time discretionary entries, favoring starts in even weeks, but do not build a system around it.

The Edge Book's other chapters read the cycle more generously. Chapter 10G reduces equity by 20% to 30% in odd weeks through ETF rotation. Card 09 in Chapter 13F permits an optional rotation between 1.0 and 0.75 times equity in a tax-deferred account. This example is the strictest of the three readings, and in a taxable account it is the safer default.

What it teaches

Implementation costs determine whether an overlay is worth running. An overlay worth 10 to 30 bps, drowned by 20 to 40 bps of tax friction, has a negative expected value (EV). The framework catches this through the score for execution, XX.

7 · Example 6: the end-of-quarter rebalance, with its sign

The question. With the first quarter (Q1) ending in 5 days, SPX is up 9% for the quarter and the 10-year Treasury note is down 1%. Should you trade the end-of-quarter (EOQ) rebalance, and in which direction?

The setup. In Q1, SPX is up 9% and ZN, the 10-year Treasury note future, is down 1%. The divergence is about 10%, since stocks outperformed bonds by 10 percentage points, and you are considering the EOQ rebalancing trade of Chapter 10G.

Worked example: Front-running a rebalance

Step 1: check the divergence threshold. Chapter 10G's rule requires a divergence of more than 1.5%, and 10% qualifies. Its approximation says a 60/40 portfolio drifts by about 0.6×0.4×10%=2.4%0.6 \times 0.4 \times 10\% = 2.4\% of its value, a sizeable flow to trade ahead of.

Step 2: get the direction right. This is the corrected sign, and the chain runs as follows:

Stocks outperformed bonds, so 60/40 funds are now overweight stocks. Rebalancers are about to sell stocks and buy bonds. Front-running means doing the same thing first: short ES, long ZN.

A reviewer of the Edge Book's first version caught this sign reversed in the original framework. Restated plainly: if equities outperformed bonds during the quarter, you go short equities and long bonds.

Step 3: size each leg. For the first few quarters of your own data, risk 0.5% of the portfolio per leg, which on $1 million is $5,000 a leg.

  • ES: at a price of about 5,800 and $50 a point, one contract is 5,800×50=$290,0005{,}800 \times 50 = \$290{,}000 of notional. A 1% adverse move costs $2,900, inside the $5,000 budget, while two contracts would risk $5,800, so hold 1 contract.
  • ZN: at a price of about 110 and $1,000 a point, one contract is $110,000 of notional, and a 1% adverse move costs $1,100. The budget would allow up to ⌊5,000/1,100⌋=4\lfloor 5{,}000/1{,}100 \rfloor = 4 contracts, where the brackets take the floor function and round down, and the Edge Book holds 1, well inside it.

So for the first few quarters the position is short 1 ES contract and long 1 ZN contract.

Step 4: time it. Enter 5 trading days before the quarter ends and exit 1 to 3 trading days into the new quarter, giving the rebalancers time to execute.

Step 5: score the conviction. Evidence is the weakest of the five factors, as the table shows:

FactorScoreWhy
Evidence EE0.55T2: a recent paper, strong but not replicated over many decades
Mechanism MM0.75The mechanism of institutional flow is solid
Regime RR0.85The large divergence supports the trade
Execution XX0.80The futures are liquid, and the spread between ES and ZN is clean to trade
Sizing SS0.80A small size for the first few quarters

The product is C=0.55×0.75×0.85×0.80×0.80=0.224C = 0.55 \times 0.75 \times 0.85 \times 0.80 \times 0.80 = 0.224, which Step 6 reads against the thresholds.

Step 6: read the score against its threshold. By the thresholds of Chapter 13B, 0.224 is below 0.3: insufficient conviction, so do not trade. The Edge Book's example calls it medium conviction and takes a test position anyway. Read as an exception, the trade is a pilot, sized so its worst quarter barely registers, whose purpose is to produce the personal evidence that could raise EE. Read by the rule, it is a pass. Chapter 13D meets the same question in a swing trade scored at 0.282.

Conclusion. The Edge Book takes the trade at small size: 1 ES short and 1 ZN long for a $1 million portfolio. Track your own P&L for 4 quarters, then evaluate. If the hit rate is above 55% and the net P&L is positive, increase the size. If the hit rate is below 50% or the net P&L is negative, suspend the trade. Card 10 in Chapter 13F and Chapter 10G are stricter about the first step, since they keep the size small for the first 8 quarters.

Four quarters are four trades, so the hit rate can only be 0%, 25%, 50%, 75% or 100%. "Above 55%" means 3 or 4 wins, and "below 50%" means 0 or 1. Suppose the trade has no edge at all, so that each quarter is a coin flip. The chance of 3 or more wins in 4 is then (4+1)/16=31%(4 + 1)/16 = 31\%, and so is the chance of 1 or fewer. The remaining 37.5% of cases end at exactly 2 wins, where neither rule fires. A trade with no edge therefore passes the test for increasing its size up to 31% of the time, which is the case for the stricter 8 quarters.

Familiar ground

Four quarters of a new trade are four patients in a pilot. Three responses in four look like 75%, but the exact 95% confidence interval for that proportion runs from about 19% to 99%. A decision rule applied to so few cases mostly measures luck, as the coin flip above shows. A pilot tells you whether to keep collecting data, not whether the treatment works, and the size stays small until the count is large.

What it teaches

Untested live strategies start small, since the low score reflects genuine uncertainty about whether a retail account can replicate a recent academic paper. Size grows with your personal evidence, not with the paper's claims.

8 · Example 7: the VIX filter fires on an open position

The question. You hold 3 contracts of XSP ATM monthly puts, cash-secured, at your full size. The VIX divided by the VIX3M has just closed above 1.05 for the third day running. What do you do?

The setup. The three puts were sold at the money with XSP at 600, for a hypothetical $15 each, and they are now 22 days from expiry. SPX has dropped 4%, so XSP stands at 576, and the filter has triggered.

Worked example: Following a kill rule in stress

Step 1: read the kill rule. Chapter 10H's rule for a ratio above 1.05 for 3 closes is to halt new sales and to reduce the existing premium-selling sleeve by 50%. "Reduce by 50%" means closing half of the existing positions, not just stopping new entries.

Step 2: mark the position, and close half of it. Each put is now $24 in the money (ITM). With 22 days left and implied volatility raised, suppose each costs $30 to buy back: $24 of intrinsic value and $6 of time value. Each is down 30−15=$1530 - 15 = \$15, or $1,500 a contract, and the three are down $4,500 together.

Half of three is one and a half, so you close one contract or two. Neither is closer to the rule, since closing one leaves two open, a cut of a third, while closing two leaves one, a cut of two thirds. The Edge Book closes one and calls that the conservative rounding, because it trades less. If you read the rule as a limit on risk, closing two is the more cautious choice. Buying back one costs $3,000 and locks in $1,500 of loss on that contract.

Step 3: answer "if I hold, it might recover". The critical operational point is that the kill rule is pre-committed. It exists because in stress, intuition tells you to hold and hope, and it overrides intuition for three reasons:

  • Stress regimes can deepen: in March 2020 the VIX went from 28 to 82 in 8 days.
  • The rule is calibrated to cumulative outcomes across many cycles, not to individual trades.
  • Following it is what allows the strategy to compound across those cycles.

If you override the rule once, you override it every time. Discipline exists only if it binds in stress.

Step 4: plan the return. Halt new entries until VIX/VIX3M has closed below 1.00 for 5 days, then re-enter in phases: 25%, then 50%, then 100% of the target size over 3 weeks. The premium you forgo during the halt is an opportunity cost, about 0.3% of the portfolio over a typical halt.

Step 5: score the halt itself. Every factor is high, because the regime the rule was written for has arrived:

FactorScoreWhy
Evidence EE0.90The filter rules rest on T1 to T2 evidence
Mechanism MM0.85A clear mechanism of stress
Regime RR0.95The filter has triggered, so the regime supports the action
Execution XX0.85Closing a contract is easy
Sizing SS0.95The action preserves the portfolio's survivability

The product is C=0.90×0.85×0.95×0.85×0.95=0.59C = 0.90 \times 0.85 \times 0.95 \times 0.85 \times 0.95 = 0.59, high conviction in the halt.

Conclusion. Buy back 1 of the 3 contracts, halt new entries and wait for the filter to normalize, without overriding the rule.

What it teaches

Pre-committed kill rules exist to override behavioral intuition. In stress, intuition says "hold and hope", and the rule says "trim and survive". Long-run compounding requires the rule to win these arguments. The conviction score for following the rule is high, 0.59, and that is what good operational discipline scores.

9 · Example 8: selling premium into one company's earnings

The question. NVDA reports earnings tomorrow, with its implied volatility (IV) at 75% against a historical average of 35%. The IV crush after the report could be 30 volatility points or more. Should you sell premium?

The setup. With NVDA at $850, the ATM call expiring in 3 days costs $35 and the ATM put $32, at IV of 75%. The expected move over the next day or two is about $45, 5.3% of the price.

Worked example: Pricing a short straddle into a report

Step 1: classify the source. This is single-name earnings short volatility, a category Chapter 10I rejects for retail accounts.

Step 2: recall the finding. Adams and Neururer (2020) found that for single names at retail size, naive earnings short volatility has a negative mean despite a positive median. Most of the time you collect a small premium, and occasionally you lose much more.

Step 3: lay out the distribution. Selling both options, a short straddle, collects 35+32=$6735 + 32 = \$67, 7.9% of the price, so it breaks even at 850±67850 \pm 67: $783 and $917.

  • The most likely outcome: the company beats and the stock moves $30. One option expires worthless and the other costs $30, so you keep 67−30=$3767 - 30 = \$37, most of the premium.
  • The tail outcome: guidance is cut and the stock drops 12%, or $102. The put then costs you 102−32=$70102 - 32 = \$70 beyond its premium, and a deeper drop costs more.

The Edge Book's rough model treats each option sold as a bet, which wins about $15 on average in three cases out of four and loses about $60 in the fourth:

0.75×15−0.25×60=11.25−15=−3.75 \begin{aligned} &0.75 \times 15 - 0.25 \times 60 \\ &\quad = 11.25 - 15 = -3.75 \end{aligned} (13E.3)

That is about −$4 per side: a negative expected value, which matches the Adams-Neururer finding.

Step 4: answer "the IV is high, so the market expects a big move". The framing that "IV is high" assumes you have an edge in predicting whether the move exceeds what is implied, and you have no systematic edge there. The negative mean that Adams and Neururer found is the average across many such earnings events with elevated IV.

Step 5: note the institutional version. Run across 200 or more names at once, as in the institutional study of Cao, Han, Tong and Zhan (2022), the strategy earns an edge built on the dispersion between names (Chapter 10I). That construction is what earns, and one name alone cannot reproduce it.

Step 6: score the conviction. Evidence and sizing are the weakest of the five factors:

FactorScoreWhy
Evidence EE0.30T3 at the level of a single name in a retail account
Mechanism MM0.40The mechanism is real but heavily skewed against a retail single-name seller
Regime RR0.50No specific support from the regime
Execution XX0.70NVDA's options are liquid
Sizing SS0.30The single-name tail risk is huge relative to the premium

The product is C=0.30×0.40×0.50×0.70×0.30=0.013C = 0.30 \times 0.40 \times 0.50 \times 0.70 \times 0.30 = 0.013, effectively zero and far below the threshold of 0.3.

Conclusion. Do not sell premium on the NVDA report. If you must trade it, prefer a calendar spread, long a longer-dated option and short a shorter-dated one, which captures the IV crush with a bounded downside. Even the calendar spread earns medium conviction at best on a single name.

What it teaches

The conviction framework identifies strategies rejected at retail level even when the narrative is compelling. "Volatility at 75 against a historical 35" is a compelling pitch, and the framework catches three things behind it:

  1. Single-name earnings short volatility has a negative mean for retail accounts, as Adams and Neururer found.
  2. The institutional "edge" comes from dispersion across many names, not from the pricing of one.
  3. The tail risk dominates the small premium collected.

10 · Example 9: the put spread and the LEAP

The question. A "professional-style" trader pitches this: "Sell 1-year SPX 4400/4200 put spreads to fund 2-year SPX 5000 LEAP calls. The premium pays for the LEAP. You get leveraged equity exposure with VRP edge." Should you do it? A LEAP is a long-dated listed option, one of the LEAPS.

The setup. The numbers are illustrative and per unit of the index, with SPX at 5,000. Selling the 1-year 4400/4200 put spread collects $42, and because the strikes are $200 apart its maximum loss is 200−42=$158200 - 42 = \$158. Buying the 2-year 5000 LEAP call costs $400, so net you pay 400−42=$358400 - 42 = \$358 for about 0.50 of LEAP delta on SPX at $5,000.

Worked example: Decomposing leverage dressed as edge

Step 1: decompose the structure. Each leg has its own Greeks and costs:

  • The long LEAP call: a delta of about 0.50 and a cost of about $400, which is 8% of SPX's notional. Its embedded financing costs 50 to 150 bps a year in embedded leverage drag.
  • The short put spread: positive theta, negative vega, a bounded loss and a delta of roughly +0.10.
  • Combined: a total delta of about 0.60 for a net cost of $358. The exposure per dollar is 0.60×5,000/358=8.40.60 \times 5{,}000/358 = 8.4 times the capital paid.

Chapter 10I calls the structure about 1.4 times SPX exposure, which describes an account holding several of them. One structure on SPX, at 100 times the index, costs $35,800 and carries 0.60×5,000×100=$300,0000.60 \times 5{,}000 \times 100 = \$300{,}000 of exposure. A $1 million account that wants $1.4 million of exposure holds about 4.7 of them, for about $167,000, and keeps the rest in cash.

Step 2: compare with ES futures. At SPX 5,000, one ES contract is 50×5,000=$250,00050 \times 5{,}000 = \$250{,}000 of notional, with margin of about $15,000. To match the structure's delta of 0.60 on that notional, hold 0.6 of a contract, $150,000 of exposure.

  • Capital: ES needs about $9,000 of margin, 0.6 of $15,000, and it is a deposit you get back. The structure needs 150,000/3,000×358=$17,900150{,}000/3{,}000 \times 358 = \$17{,}900 of premium, which is spent.
  • Financing: futures build in a financing cost of about SOFR plus 10 to 20 bps, about 4.6% to 4.7% a year. On a full contract's $250,000 that is about $11,500 a year, and on $150,000 about $6,900 to $7,050. The LEAP's price carries the same rate plus its drag of 50 to 150 bps, an extra $750 to $2,250 a year on $150,000, where the futures' spread costs $150 to $300.

The Edge Book's rough estimate is that the structure costs 50% to 100% more than ES futures for the same exposure. The capital comparison supports the upper end, at about twice as much. The financing gap is smaller, but it runs the same way.

Step 3: look for the "VRP edge". The short put spread collects $42, and the Edge Book's rough distribution for it is in the table.

OutcomeProbabilityP&L
Expires worthless60% to 70%+$42
Partial loss25% to 30%−$30 to −$80
Full loss5% to 10%−$158

At the middle of each range the expected value is 0.65×42−0.275×55−0.075×158=+$0.330.65 \times 42 - 0.275 \times 55 - 0.075 \times 158 = +\$0.33, about zero. The most favorable reading, with the highest chance of a win and the smallest losses, gives 0.70×42−0.25×30−0.05×158=+$140.70 \times 42 - 0.25 \times 30 - 0.05 \times 158 = +\$14, and the least favorable −$14.60. The Edge Book's own estimate of +$15 to +$20 before friction, and about +$10 after it, sits above even the favorable reading. Grant it anyway: $10 is 10/358=2.8%10/358 = 2.8\% a year on the $358 outlay. Against the LEAP's drag of 50 to 150 bps, the net edge over simple leverage runs from −1.5% to +2.3% a year for a spread earning between nothing and 2.8%, which is within noise.

Step 4: follow the path through S2. Take SPX down 20% and the VIX up 25 points.

  • ES: one contract loses 20% of its $250,000 of notional, which is $50,000. Its margin requirement roughly triples, from about $15,000 to about $45,000, but in a $1 million account the cushion is clear.
  • The structure: the LEAP call loses on its delta, a fall that its positive vega only partly offsets, and the Edge Book puts the loss at about 80% of its value, $320. The short put spread, now deep in the money, loses $116 of its $158 maximum. Together that is 320+116=$436320 + 116 = \$436, 122% of the $358 outlay, so the position is essentially destroyed and a forced close is likely.

ES handles the stress much better, because its loss is the index's loss, with no second leg whose margin grows as it loses.

Step 5: score the conviction. Three of the five factors sit at 0.30, as the table shows:

FactorScoreWhy
Evidence EE0.30No real edge beyond leverage
Mechanism MM0.30The claim of a VRP edge is wrong
Regime RR0.60Neutral, since the structure is leverage whatever the regime
Execution XX0.50Multiple legs and a complex roll
Sizing SS0.30A worse path than the alternatives

The product is C=0.30×0.30×0.60×0.50×0.30=0.008C = 0.30 \times 0.30 \times 0.60 \times 0.50 \times 0.30 = 0.008, effectively zero and far below the threshold of 0.3.

Conclusion. Do not trade the put spread and LEAP combination. If you want leveraged equity exposure, three routes give equivalent or better economic exposure, with less complexity and better path properties:

  1. ES futures, best for active traders, with Section 1256 taxation and clean financing.
  2. A 2 times ETF such as SSO, for passive holders, at an expense ratio of 0.85%.
  3. Box spread financing plus SPY, for sophisticated accounts under portfolio margin.

The LEAP and put spread structure is leverage with extra steps, dressed as edge.

What it teaches

Decomposition kills false claims of edge: once you walk through the Greeks, the financing and the path, edges that depend on complexity often vanish. The simple alternatives, futures and leveraged ETFs, usually win on operational realism.

11 · Example 10: sizing from a stress loss

The question. You want to add a new short volatility strategy, XSP put-writing, to the portfolio. The largest monthly loss you accept on this sleeve in S2, SPX down 20% with the VIX up 25, is 5% of the whole portfolio. How big can the position be?

The setup. The total portfolio is $1 million, so the largest acceptable S2 loss on the sleeve is 5% of it, $50,000. The strategy is XSP ATM monthly puts, cash-secured.

Worked example: From a loss budget to a contract count

Step 1: estimate the S2 loss per contract. Take an ATM XSP put struck near the current price of 600. In S2 the index falls 20%, so XSP falls to 480, and the put is deep in the money with an intrinsic value of $120. Sold for $12 of premium, it has lost about 120−12=$108120 - 12 = \$108 per unit at S2.

Step 2: compute the maximum count. With the multiplier of 100, the loss is about $10,800 a contract. The budget allows 50,000/10,800=4.650{,}000/10{,}800 = 4.6 contracts, so round down to 4.

Step 3: verify against S3. In S3, SPX falls 35%, XSP falls to 390, and the put's intrinsic value is $210. The loss is about 210−12=$198210 - 12 = \$198, close to $200, or about $20,000 a contract, so four contracts lose about $80,000, 8% of the portfolio. That exceeds the S2 budget, but it should still be recoverable: by Chapter 1E a loss of 8% needs a gain of 0.08/0.92=8.7%0.08/0.92 = 8.7\% to repair. If 8% would cause operational trouble, such as a margin breach or a behavioral capitulation, reduce to 3 contracts.

Step 4: verify the cash collateral. Each contract needs its strike in cash, 600×100=$60,000600 \times 100 = \$60{,}000, and the $1,200 premium you receive supplies part of it, leaving $58,800 of your own. Four contracts tie up $240,000 of collateral, 24% of the portfolio. That is operationally feasible: it reduces the portfolio's effective exposure, but it eliminates the path risk of margin.

Step 5: write the sizing equation. A reviewer of the Edge Book proposed the rule that turns the budget into a count. The number of units nn you may hold is

n≤⌊BexpLmax⌋ n \le \left\lfloor \frac{B_\text{exp}}{L_\text{max}} \right\rfloor (13E.4)

Here BexpB_\text{exp} is the explicit loss budget in dollars and LmaxL_\text{max} the maximum loss per unit, per contract in the stress. The floor brackets ⌊ ⌋\lfloor\ \rfloor round down to a whole number. With Bexp=$50,000B_\text{exp} = \$50{,}000 and Lmax=$10,800L_\text{max} = \$10{,}800, the rule gives n≤4.6n \le 4.6, so you may hold n=4n = 4 contracts. Chapter 13C runs the same budget with the round $10,000 a contract of Card 02 and also arrives at 4.

Step 6: score the conviction. The sizing score rises because the size now comes from the budget:

FactorScoreWhy
Evidence EE0.85T1 evidence
Mechanism MM0.90A clear mechanism
Regime RR0.85A calm regime, assumed
Execution XX0.90XSP is liquid
Sizing SS0.90Sized to the budget, and cash-secured

The product is C=0.85×0.90×0.85×0.90×0.90=0.53C = 0.85 \times 0.90 \times 0.85 \times 0.90 \times 0.90 = 0.53, high conviction, so allocate.

Conclusion. Sell 4 contracts of XSP ATM monthly puts, with a largest S2 loss of about $43,200, 4.3% of the portfolio, and a largest S3 loss of about $80,000, 8%. The cash collateral required is about $240,000, and the kill criteria are those of Example 7.

What it teaches

Position sizing should come from an explicit loss budget, not from intuition. The rule n≤⌊Bexp/Lmax⌋n \le \lfloor B_\text{exp}/L_\text{max} \rfloor converts a subjective risk tolerance into an objective contract count. This is the operational meaning of "size for survivability".

12 · What the ten examples teach together

ExampleDecisionScoreVerdict
1Pitched far-OTM put-writing0.010Do not allocate
2VRP harvest, calm regime0.497Allocate 2 to 3 contracts
3VRP harvest, stress regime0.026No new entries; halve existing
4Trend allocation in a drought0.36Allocate 10% to 15%, built over 3 months
5FOMC rotation of SPY0.072 or 0.153No rotation; time new money only
6EOQ rebalance0.224Test size, or pass by the threshold
7Following a filter in stress0.59Buy back 1 of 3; halt
8Single-name earnings short volatility0.013Do not trade
9Put spread funding a LEAP0.008Do not trade; use futures
10Put-writing sized from a budget0.53Sell 4 contracts

Seven operational principles run through them:

  1. Pitched Sharpe ratios are paper Sharpe ratios, so apply the haircuts before you evaluate anything.
  2. The conviction framework turns off in adverse regimes, which is why selectivity is mostly not trading.
  3. Kill rules exist to override behavioral intuition, so pre-commit them while you are calm.
  4. Decomposition kills false claims of edge once you walk through the Greeks, the financing and the path.
  5. Position size comes from an explicit loss budget, not from intuition or from the strength of a conviction score.
  6. Analysis across several domains surfaces problems that a look at any single dimension misses.
  7. The simpler alternative usually wins, since futures and ETFs beat complex options structures more often than not.

These are the principles distilled into chains of reasoning. When you meet a new strategy, run it through the same kind of analysis.

In practice

Write each chain down before you act, in the trade journal of Chapter 13H: the haircut, the filters, the stress floor, the five scores and the contract count. Record the score beside the outcome, so that over a few years the record can answer a question no single example can. Chapter 13G's five-year revalidation asks it: do your high-scoring decisions actually beat your low-scoring ones? Where your intuition and the score disagree, the written chain shows which one skipped a step.

When it fails

The chain is only as good as its inputs. Every factor score in these examples is a judgment, and two careful readers could score the same trade either side of a threshold, as Example 6 shows. Stress estimates are only estimates: several of the Edge Book's own figures sit below the floor that intrinsic value sets. A first-order estimate can miss a third of the loss. And the regime can move faster than any score, as it did when the VIX rose from 28 to 82 in 8 days in March 2020.

Decision rule

Run every portfolio decision through the same chain, in this order:

  • Haircut the claim. Cut a short volatility Sharpe ratio by 30% to 50% for skew, then apply the retail haircut, and compare the result with simply holding SPX.
  • Read the filters. If VIX/VIX3M or realized volatility says halt, stop there (Chapter 10H).
  • Stress-test at the floor. Price S1 to S3 from intrinsic value less premium, never from delta alone.
  • Score the conviction. Pass below 0.3, allocate small or in phases from 0.3 to 0.5, and allocate at 0.5 or above.
  • Size from the budget. Hold n≤⌊Bexp/Lmax⌋n \le \lfloor B_\text{exp}/L_\text{max} \rfloor, then check that S3 is recoverable.
  • Write the kill rule first, and follow it when it fires.
Common mistake: counting premium as profit

A put-writing sleeve that collects 4% to 6% of the portfolio a year in premium does not earn 4% to 6%. The months in which the index falls through the strike pay much of it back. What remains, 2% to 4% a year on the collateral, is the premium for bearing the crash. Judge a short option strategy by its net after those months, never by what it collects.

Common mistake: trusting a first-order stress estimate

Multiplying a short put's delta by the size of a fall understates the loss whenever the fall is large. Gamma steepens the put's delta as the index drops through the strike, so the loss grows faster than the fall. In Example 2 the delta estimate gave $3,000 a contract in S1, against a floor of $4,200 to $4,800. Price every stress from the option's value at the stressed level, which for a put is at least its intrinsic value.

The Edge Book calls this chapter the operational heart of its framework: the place where concept becomes judgment. Chapter 13F compresses these chains into one-page setup cards. Chapter 13G sets the sleeves in a portfolio, with kill criteria at three levels and a cadence for reviewing them, and Chapter 13H adds the portfolio's total exposure to volatility. The reference chapters R1 to R4 then collect the glossary, the formulas and the checklists.

What to carry forward
  • A pitched Sharpe ratio for short volatility shrinks by about 58% once skew and retail frictions are counted, and a benign backtest decade says nothing about the tails.
  • The same VRP harvest scores about 0.50 in a calm regime and 0.026 in stress: the regime and sizing scores, not the evidence, decide when to trade.
  • Stress-test short options from intrinsic value less premium, because first-order estimates from delta understate large losses.
  • Size from the loss budget with n≤⌊Bexp/Lmax⌋n \le \lfloor B_\text{exp}/L_\text{max} \rfloor, check S3, and write the kill rule before the trade.
  • Complex structures, such as a put spread funding a LEAP, usually decompose into leverage that futures or ETFs provide more cheaply and with a safer path.

13 · Check yourself

Question 1

A newsletter pitches selling SPX puts at 5 delta, far out of the money, with a backtested Sharpe ratio of 1.0 from 2013 to 2022. Which examples apply, and what does the chain say?

Answer

Example 1 applies directly: cut 35% for skew and apply a retail factor of 0.65, which gives 1.0×0.65×0.65=0.421.0 \times 0.65 \times 0.65 = 0.42. That is below SPX's retail-adjusted 0.5 even before asking about the tails. A decade with one brief crash spike says nothing about S2 or S3, where far-OTM put-writing can lose most of the sleeve. With evidence, sizing and mechanism scores like Example 1's, the conviction score is near zero, so do not allocate.

Question 2

State the position-sizing equation. What inputs does it need, and what does it give for a $600,000 portfolio with a 4% S2 budget and puts that lose $10,800 each in S2?

Answer

The rule is n≤⌊Bexp/Lmax⌋n \le \lfloor B_\text{exp}/L_\text{max} \rfloor: the explicit loss budget in dollars divided by the maximum loss per unit in the stress, rounded down. The budget is 0.04×600,000=$24,0000.04 \times 600{,}000 = \$24{,}000, so the rule allows n≤⌊24,000/10,800⌋=⌊2.2⌋=2n \le \lfloor 24{,}000/10{,}800 \rfloor = \lfloor 2.2 \rfloor = 2 contracts. Then check S3: at about $20,000 a contract, two lose $40,000, 6.7% of the portfolio.

Question 3

Why does the conviction score for following a kill rule tend to be high in stress?

Answer

The regime score RR is high precisely because the filter has triggered, so the stress the rule was written for is present. Closing a liquid contract scores well on execution, and the action preserves survivability, so SS is high too. In Example 7 the product is 0.59, which makes following the rule the high-conviction trade and the urge to hold the low-conviction one.

Question 4

What is the difference between a Sharpe haircut and the conviction score?

Answer

A haircut revises an estimate, turning a paper Sharpe ratio into a realistic one by removing skew and implementation frictions. The conviction score is a gate across five domains, including the current regime and the survivability of the size. A strategy can pass the haircut and fail the gate. Example 3 keeps the VRP's strong evidence and mechanism, yet scores 0.026 because the regime and sizing collapsed.

Question 5

Why do simpler alternatives, such as futures and ETFs, usually beat complex options structures?

Answer

Each extra leg adds costs, operational risk and chances for the behavioral haircut, so complex multi-leg structures take the largest haircuts (Chapter 13A). Their financing is embedded and dearer: 50 to 150 bps of leverage drag in a LEAP against 10 to 20 bps above SOFR for ES. Their paths are worse too, with margin that grows as they lose. Example 9's structure lost 122% of its outlay in S2, while ES lost exactly the index's 20%.

Question 6

A strategy scores C=0.55C = 0.55, but its S2 loss at your intended size is 7% of the portfolio against a budget of 5%. What do you do?

Answer

Trade it, but smaller: the score says whether to trade, and the loss budget says how much. Resize with n≤⌊Bexp/Lmax⌋n \le \lfloor B_\text{exp}/L_\text{max} \rfloor so that S2 fits inside 5%, which here means cutting to about 5/7 of the intended size or less, then check S3 at the new size. A high score is never a reason to size up (Chapter 13B).