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Lesson 22

Risk, diversification & required returnModule 04 · Accounting & financial reasoning

IGNITE EXTENDED / LESSON 22

Risk, diversification & required return

Which risks should affect a required return?

A risk-classification and discount-rate rationale.

S33 · S311 / 29
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22 / OpeningRisk, diversification & required return

The decision and the learning goals

  • Distinguish total risk from non-diversifiable risk
  • Explain diversification without assuming all risk disappears
  • Relate investor required return to a valuation assumption
90-minute workshopOpening 5 minConcepts and original examples 35 minPractice 25 minDebrief 15 minReview 10 min
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22 / TheoryRisk, diversification & required return

Expected return is a probability-weighted mean

An expected return combines possible outcomes using their probabilities. It can be an outcome that never occurs in any individual scenario. The probability distribution matters because two investments can have the same mean and very different variation or downside exposure.

Specify the states, their probabilities and the return convention. A forecast based on historical averages also requires an argument for why those observations are informative about the future. The source chapter’s historical market charts describe their stated periods and are used here to explain risk measurement.

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22 / TheoryRisk, diversification & required return

Portfolio risk depends on co-movement

An investment’s contribution to portfolio risk depends on how its outcomes move with the other investments. Imperfectly related exposures can partly offset one another. The source’s portfolio diagrams explain why combining assets can reduce variation without eliminating every source of risk.

Company-specific events may diversify across a sufficiently broad portfolio. Common shocks can affect many holdings together. The benefit therefore depends on the weights, variances and covariances, rather than simply the count of investments. Correlations can also change across conditions.

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22 / TheoryRisk, diversification & required return

Expected return

E[R] = SUM OF PROBABILITY × RETURN
Possible outcomes
Define returns for the same holding period.
Probabilities
State the assumptions; they are not known merely because a model uses them.

Illustrative: 50% chance of +20% and 50% chance of −10% gives expected return +5%.

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22 / TheoryRisk, diversification & required return

Expected return and risk

Expected return is a probability-weighted average. Risk concerns the possible deviations and their consequences. The average alone cannot describe the experience of holding the investment.

Expectation

A probability-weighted average of possible returns.

Risk

The distribution and relevant consequences of outcomes. The average alone does not describe them.

Worked application

Illustrative application: one investment returns 10% with certainty in a toy model. Another has equally likely returns of −20% and 40%, also averaging 10%. A person unable to absorb the loss faces a materially different decision despite the equal mean.

Examine outcomes and their co-movement with the rest of the portfolio, using the stated probabilities as assumptions rather than observations.

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22 / TheoryRisk, diversification & required return

Equal expected return, different variation

Illustrative investmentOutcome 1 (50%)Outcome 2 (50%)Expected return
A+20%−10%+5%
B+8%+2%+5%

These invented two-state outcomes illustrate variation; they are not investment recommendations.

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22 / TheoryRisk, diversification & required return

Diversification depends on co-movement

  • Combining exposures can reduce risk when their outcomes do not move together perfectly.
  • Company-specific risks can partly offset in a diversified portfolio.
  • Common market risks do not disappear merely because there are many holdings.
  • The effect depends on weights, correlations and the underlying exposures.
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22 / TheoryRisk, diversification & required return

Beta and total volatility measure different relationships

Total volatility describes variation in an investment’s own return. Beta describes sensitivity to the chosen market return in the model. A volatile asset can have modest beta if much of its variation is unrelated to that market.

The capital asset pricing model relates required return to a risk-free rate, beta and a market risk premium. It is a model with assumptions, not a direct price quote for every private venture. Illiquidity, financing constraints and concentrated exposure complicate its application to early businesses.

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22 / TheoryRisk, diversification & required return

The relevant risk depends on whose decision is being made

A diversified fund and a founder can evaluate the same venture while facing different personal consequences. The founder may have employment, wealth and years of effort tied to it. The fund can evaluate the venture as one exposure within a portfolio.

Separate the project’s possible cash outcomes from the decision maker’s risk capacity and preferences. A financing structure can redistribute outcomes without making the operating uncertainty disappear. This distinction connects the risk lesson to investor incentives and the economics of financing terms.

S33 · S3110 / 29
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22 / TheoryRisk, diversification & required return

Systematic and idiosyncratic risk

Idiosyncratic risk concerns events particular to an investment. Systematic risk concerns exposure to shared market movements. Diversification affects them differently.

Systematic

Risk associated with broad market movements that remains relevant to a diversified investor.

Idiosyncratic

Risk specific to an exposure that may be reduced through diversification.

Worked application

Illustrative application: a single plant outage may be specific to one company. A broad decline in demand can affect many holdings together. Adding many similar businesses may therefore leave substantial shared exposure even when company-specific events average out more.

A founder concentrated in one company can experience risks that a diversified investor does not price in the same way.

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22 / TheoryRisk, diversification & required return

Beta describes market sensitivity

BETA = COVARIANCE WITH MARKET ÷ MARKET VARIANCE
Interpretation
Sensitivity to the specified market return in the model.
Limit
It is not a startup’s probability of failure or a complete account of business risk.
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22 / TheoryRisk, diversification & required return

A required-return illustration

r = RISK-FREE RATE + BETA × MARKET PREMIUM
Illustrative inputs
3% risk-free rate, beta 1.2 and 5% market premium.
Model result
3% + 1.2 × 5% = 9%.
Context
Illiquidity or other features may matter; avoid counting the same risk twice.

These are teaching assumptions, not current rates or a ready-made startup discount rate.

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22 / TheoryRisk, diversification & required return

A founder and a fund can experience different risk

  • The founder’s income, time and wealth may be concentrated in one venture.
  • A diversified fund can hold many exposures.
  • The same venture risk can therefore affect preferences differently.
  • Keep portfolio risk, project execution risk and personal constraints distinct.
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22 / Deep diveRisk, diversification & required return

Where each Relay risk belongs

Illustrative classification for the $300k second-EHR integration.

Specific risks reduce expected cash flows; systematic and liquidity risks raise the required return. Choose one place for each risk.

RiskTypeWhere to represent itHow
EHR restricts API accessSpecificCash flowsScenario with a stated probability that gross profit stops
Clinic uptake below 39 clinicsSpecificCash flowsProbability-weighted uptake; compare with break-even of about 37
Engineering delaySpecificCash flowsShift receipts later; add cost of delay
Clinic budgets fall in a recessionSystematicRateBeta x market premium
Shares cannot be sold before exitLiquidityRateLiquidity premium
S33 · S3115 / 29
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22 / Source insightRisk, diversification & required return

Value additivity and the chapter summary on risk and return

Explains that investors can diversify more cheaply than firms, so diversification adds no value at the firm level (PV(AB) = PV(A) + PV(B)); the summary reports historical averages of about 4.0% a year for US Treasury bills and 11.1% for common stocks over 109 years, a 7.1% premium, and market standard deviation of about 15% to 20%.

Two benchmarks follow: discount safe projects at the risk-free rate and average-risk projects at the market's expected return. A venture like Relay sits outside both, which is why the rate needs an argument. The historical figures describe the chapter's sample period, not today's inputs.

Source insight · S33 · PDF page 2316 / 29
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22 / Reading debriefRisk, diversification & required return

Introduction to Risk and Return / summary

Selected reading: PDF pages 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23

The chapter develops measures of uncertain returns and explains diversification through the co-movement of holdings. An investment’s contribution to a portfolio depends on more than its own variability.

  • Return has a distribution

    An expected return summarizes possible outcomes and probabilities. Variance and standard deviation describe dispersion around that expectation.

  • Historical data requires interpretation

    The chapter compares long-run asset returns and risk premiums. Those observations have sampling uncertainty and do not directly establish future expected returns.

  • Co-movement drives diversification

    Combining holdings can reduce exposure to company-specific outcomes. Shared market movements limit the risk that adding similar holdings can remove.

  • Beta asks a portfolio question

    Beta measures sensitivity to the market in the stated model and estimation period. It differs from the total standard deviation of an individual holding.

Reading debrief · S33 · PDF pages 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 2317 / 29
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22 / Reading debriefRisk, diversification & required return

Introduction to Risk and Return / discussion

Selected reading: PDF pages 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23

Critical points

An average and a guarantee

Equal expected returns can accompany very different possible losses. The mean does not describe the range of outcomes a holder must be able to bear.

Diversification and common exposure

A large number of holdings can still move together. Examine relationships among returns, not only the count of investments.

The holder’s position

A diversified investor and a founder concentrated in one venture face different total exposures. Distinguish the portfolio model from the person’s complete financial situation.

Reading debrief · S33 · PDF pages 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 2318 / 29
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22 / Source insightRisk, diversification & required return

LPs' perspective: compensation for time and risk

An investor who commits $1 today expects on average $1 x (1 + r)^t at time t, and the slide asks what the required rate r should be.

The rate is set by the investor's alternatives, not by the project. Relay's 20% or 30% hurdle is a claim about what capital of similar risk and illiquidity earns elsewhere.

Source insight · S31 · PDF page 519 / 29
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22 / Source insightRisk, diversification & required return

Required return = risk-free rate + risk premium + liquidity premium

Builds the required rate from US Treasury yields, a risk premium for non-diversifiable (systematic) risk measured as beta times the market risk premium, and a liquidity premium for assets that cannot be sold quickly without a discount.

Idiosyncratic risk earns no premium in this framework because diversified investors can remove it. That is the reason Relay's company-specific risks (ClinicOS revoking API access, uptake) belong in the cash-flow scenarios rather than in an inflated rate.

Source insight · S31 · PDF page 620 / 29
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22 / Source insightRisk, diversification & required return

From LP required return to the VC's terms on each deal

A road from LPs' required return (risk-free, beta, liquidity premium) to their target net multiple, the VC's gross multiple after fees and carry, the outsized return each deal must be able to produce because failure rates are high, the VC's ownership at exit, and the valuation offered today.

This chain explains why VC hurdle rates look far above CAPM: they are applied to success-case projections and must cover failures, fees and illiquidity. It connects this lesson's rate to the VC-method valuation in lesson 31.

Source insight · S31 · PDF page 1721 / 29
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22 / ApplicationRisk, diversification & required return

A risky venture inside a portfolio

The finance materials distinguish investor required returns and portfolio economics from the venture’s operating uncertainties. A customer, execution or funding risk needs an operational response; labeling it “beta” does not produce a reliable valuation.

Which risks can this investor diversify, and which still affect the decision?

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22 / Current practiceRisk, diversification & required return

Current practice: today's inputs for the rate

Higher risk-free rates raise every hurdle

Damodaran's data page lists a US Treasury rate of 5.29% as the dollar risk-free rate and an implied US equity risk premium of 4.20% as of October 1, 2026, with alternative estimates from 3.30% to 5.67%. The textbook's 3% risk-free illustration understates today's base.

Use current inputs, state their date

A CAPM benchmark built with these inputs (about 10.3% at beta 1.2) is a floor for a diversified investor, not a venture rate. Record the source and date of each input in the model so the rate can be updated rather than inherited.

Sources: Aswath Damodaran, NYU Stern: home page with current implied ERP · BVWire: Damodaran posts his first data update for 2026

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22 / PracticeRisk, diversification & required return

Classify risk before choosing a rate

Fictional venture risks: one key engineer may leave; a recession could reduce demand across customers; inventory can expire; the investor may need cash before an exit.

Your task

Classify the mechanisms. Explain which are operational, market-related or liquidity-related and why one arbitrary extra discount rate is not a complete response.

S33 · S3124 / 29
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22 / DebriefRisk, diversification & required return

Worked answer and reasoning

  • Engineer loss and inventory exposure are specific operating risks; plan mitigation and assess their cash-flow effects.
  • A broad demand shock can introduce correlated market exposure. Illiquidity concerns the ability to exit without unacceptable cost.
  • Use consistent treatment of cash-flow scenarios and required return, and avoid pretending an unsupported rate resolves every uncertainty.
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22 / Venture stepRisk, diversification & required return

Venture step: Choose and defend Relay's required return

Relay · venture step 22

The second-EHR integration ($300,000 now; $150,000 of incremental gross profit a year for three years) has NPV +$15.97k at 20% and -$27.58k at 30%. Daniel argues for 20%; the seed lead, used to venture hurdle rates, argues for 30%. Relay's specific risks include ClinicOS-style API access terms at the second EHR, clinic uptake, and a two-person engineering team that would be fully committed for months.

Your task

Write a one-page rate rationale: classify Relay's risks, say which belong in the cash flows and which in the rate, state the rate and the cash-flow case it applies to, and show why the decision flips between 20% and 30%.

Relay · illustrative venture26 / 29
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22 / Venture stepRisk, diversification & required return

Venture step: worked reasoning

  • Classify: API access loss, uptake shortfall and engineering delay are specific (idiosyncratic) risks; a broad cut in clinic budgets in a recession is systematic; inability to sell Relay shares before an exit is illiquidity. Specific risks belong in probability-weighted cash flows, because a diversified investor demands no premium for them and a rate cannot represent a binary event such as API loss.
  • A CAPM benchmark with current inputs (5.29% Treasury rate, 4.20% implied equity premium, illustrative beta 1.2) gives 5.29% + 1.2 x 4.20% = 10.3%. The gap to 20% to 30% covers illiquidity and the fact that the $150k is a success case, not an expected value.
  • Using 30% on the $150k plan is mathematically similar to using 20% on 86% of it: 150 x 1.8161 / 2.1065 = $129.3k a year. The 10-point rate difference is a 14% haircut to the forecast, which is why NPV moves from +$15.97k to -$27.58k.
  • Recommendation: build an expected-value case (for example, explicit probabilities of API restrictions and slower uptake) and discount it at 20%; do not also apply 30%, which would count the same risks twice. If the board will only accept the plan case, 30% is the consistent rate and the project fails.
  • Either way the decision is close and turns on uptake, which is cheaper to learn than to assume. That is the case for the $80,000 pilot in lesson 23.
Relay · illustrative venture27 / 29
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22 / DebriefRisk, diversification & required return

Reasoning traps

Counting the same risk twice

Haircutting cash flows for API loss and slow uptake and then also discounting at a venture rate built to cover those risks understates value. Pair expected cash flows with an expected-return rate, or plan-case flows with a hurdle rate, not both.

Beta read as a failure probability

Beta measures sensitivity to market returns. A startup's chance of failing is mainly specific risk and belongs in the cash-flow scenarios.

Founder and fund treated as the same decision maker

A diversified fund prices systematic risk; a founder with most of their wealth and career in Relay bears total risk. Disagreements about Relay's risk can reflect different positions, not different forecasts.

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22 / ReviewRisk, diversification & required return

What you can now explain

A rate rationale for Relay: risks classified by type, a CAPM benchmark of about 10.3%, a defended choice between expected flows at 20% and plan flows at 30%, and the conclusion that uptake should be tested before committing $300,000.

  • Diversified investors require a premium for systematic risk and illiquidity, not for company-specific risk, which still belongs in expected cash flows.
  • Venture hurdle rates of 20% to 30% are applied to success-case forecasts; the rate and the cash-flow case must be chosen together.
  • For Relay's integration, the 10-point rate difference equals a 14% haircut to the forecast, enough to flip NPV from +$15.97k to -$27.58k.

Next lesson: Real options & staged commitments

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