CS Executive · Corporate Accounting and Financial Management
Security Analysis: formula sheet
Key formulas
- Undervalued security
- Intrinsic value > Market price
- Signal to buy. Intrinsic value comes from fundamental analysis.
- Overvalued security
- Intrinsic value < Market price
- Signal to sell or avoid.
- Fairly priced security
- Intrinsic value = Market price
- No gain expected from trading on valuation alone.
- Fundamental analysis layers
- Economy → Industry → Company (EIC)
- Top-down order. State all three layers in answers.
- Forms of market efficiency
- Weak: past prices | Semi-strong: all public information | Strong: all information including private
- Each form includes the one before it.
- Holding period return
- Return = (D + (P1 − P0)) ÷ P0
- D is dividend or interest received, P0 is the purchase price, P1 is the end price. Multiply by 100 for a percentage.
- Expected return (with probabilities)
- E(R) = Σ (pi × Ri)
- Multiply each possible return by its probability and add. Probabilities must total 1.
- Expected return (historical data, equal weight)
- Average return = ΣR ÷ n
- Use when past returns are given without probabilities.
- Variance (with probabilities)
- σ² = Σ pi × (Ri − E(R))²
- Take the deviation from expected return, square it, weight it by probability, then add.
- Standard deviation
- σ = √σ²
- Same unit as return, so it is easier to interpret. Higher σ means higher risk.
- Variance (historical, sample)
- σ² = Σ (R − average)² ÷ (n − 1)
- Use n instead of (n − 1) if the question treats the data as the whole population. Follow the question or state your assumption.
- Coefficient of variation
- CV = σ ÷ E(R)
- Risk per unit of return. Use it to compare securities with different expected returns. Lower is better.
- Value of a redeemable bond
- V0 = Σ [I ÷ (1 + kd)^t] + M ÷ (1 + kd)^n, t = 1 to n
- I = annual interest (coupon rate × face value), kd = required return, M = redemption value, n = years to maturity.
- Annuity-factor form
- V0 = I × PVIFA(kd, n) + M × PVIF(kd, n)
- Use the present value tables given in the exam. This is the fastest way to compute the value.
- Irredeemable (perpetual) debenture
- V0 = I ÷ kd
- Use when there is no maturity date and interest continues forever.
- Zero-coupon bond
- V0 = M ÷ (1 + kd)^n
- No interest is paid. The whole return comes from the gap between price and redemption value.
- Semi-annual interest
- V0 = (I ÷ 2) × PVIFA(kd ÷ 2, 2n) + M × PVIF(kd ÷ 2, 2n)
- Halve the interest and the rate, and double the periods. Use only when interest is paid twice a year.
- Current yield
- Current yield = (Annual interest ÷ Current market price) × 100
- Ignores the capital gain or loss at maturity.
- YTM (approximate)
- YTM ≈ [I + (M − P) ÷ n] ÷ [(M + P) ÷ 2]
- P = current price. A close estimate, not exact. Use it as a starting rate for trial and error.
- YTM by interpolation
- YTM = r1 + [(V1 − P) ÷ (V1 − V2)] × (r2 − r1)
- V1 is the value at the lower rate r1 and V2 the value at the higher rate r2. P must lie between V1 and V2.
- Macaulay duration
- D = Σ [t × PV(CFt)] ÷ Σ PV(CFt)
- The denominator is the bond's present value (its price at that yield). t is the year of the cash flow.
- Modified duration and price change
- Modified duration = D ÷ (1 + y); % change in price ≈ − Modified duration × change in yield
- A linear estimate that works for small changes in yield. The minus sign shows prices fall when yields rise.
- Dividend discount model (finite holding)
- P0 = D1 ÷ (1 + ke) + D2 ÷ (1 + ke)² + … + Dn ÷ (1 + ke)ⁿ + Pn ÷ (1 + ke)ⁿ
- Use when you are given dividends for a few years and an expected selling price.
- Zero growth (constant dividend)
- P0 = D ÷ ke
- Dividend stays the same forever.
- Gordon's growth model
- P0 = D1 ÷ (ke − g)
- Valid only when ke > g. D1 = D0 × (1 + g).
- Growth rate from retention
- g = b × r
- b is the retention ratio and r is the return on equity (ROE). Use when growth is not given directly.
- Implied cost of equity
- ke = D1 ÷ P0 + g
- Rearranged Gordon's model, used when market price is given.
- P/E valuation
- Value per share = EPS × P/E ratio
- P/E ratio = market price per share ÷ EPS.
- Earnings capitalisation
- Value per share = EPS ÷ required earnings yield
- Same as using P/E = 1 ÷ earnings yield.
- Irredeemable preference share
- P0 = Preference dividend per share ÷ kp
- Fixed dividend perpetuity.
- Redeemable preference share
- P0 = Σ Dt ÷ (1 + kp)ᵗ + Redemption value ÷ (1 + kp)ⁿ
- Discount the dividends and the redemption amount at the required return.
- Simple moving average (SMA)
- SMA = (P1 + P2 + ... + Pn) ÷ n
- P is the closing price of each of the last n periods. Drop the oldest price and add the newest to roll it forward.
- Moving average crossover rule
- Price > moving average: buy signal. Price < moving average: sell signal.
- Signal comes when the price line crosses the average line. Short average crossing above long average is also a buy signal.
- Relative Strength Index (RSI)
- RSI = 100 − [100 ÷ (1 + RS)], where RS = average gain ÷ average loss
- Commonly over 14 periods. Above 70 is read as overbought, below 30 as oversold.
- Dow Theory trends
- Primary (1 year or more) > Secondary (weeks to months) > Minor (under about 3 weeks)
- Learn the three trends and their durations.
- Volume confirmation rule
- Price up + volume up = strong. Price up + volume down = weak.
- Applies the same way to downtrends.
- Weak form efficiency
- Price today reflects all past prices and volumes
- Technical analysis cannot produce consistent abnormal returns. Supports the random walk idea.
- Semi-strong form efficiency
- Price today reflects all publicly available information
- Neither technical nor fundamental analysis gives consistent abnormal returns. Insiders may still gain.
- Strong form efficiency
- Price today reflects all information, public and private
- Even insider information gives no abnormal return. Generally regarded as the least realistic form.
- Random walk
- Pₜ = Pₜ₋₁ + random change (unpredictable)
- Successive price changes are independent. Past changes do not help forecast future changes.
- Abnormal return
- Abnormal return = Actual return − Expected return
- EMH says consistent positive abnormal returns are not available using the information set of that form.
- Nesting of forms
- Strong ⊃ Semi-strong ⊃ Weak
- If a stronger form holds, the weaker forms hold too.
- Expected return of a portfolio
- Rp = Σ (wi × Ri)
- wi is the proportion invested in security i. Weights must add up to 1.
- Expected return of a security from probabilities
- E(R) = Σ (Pi × Ri)
- Pi is the probability of outcome i.
- Variance and standard deviation
- σ² = Σ Pi × (Ri − E(R))²; σ = √σ²
- Standard deviation is the usual measure of total risk.
- Two-security portfolio risk
- σp = √(w1²σ1² + w2²σ2² + 2 × w1 × w2 × ρ12 × σ1 × σ2)
- ρ12 is the correlation coefficient. Equivalent: replace ρ12σ1σ2 with covariance Cov12.
- Correlation
- ρ12 = Cov12 ÷ (σ1 × σ2)
- Lies between −1 and +1. At +1 there is no diversification benefit; at −1 risk can be reduced to zero with right weights.
- Beta of a security
- β = Cov(Ri, Rm) ÷ σm² = ρim × σi ÷ σm
- σm² is the variance of market returns.
- Portfolio beta
- βp = Σ (wi × βi)
- A simple weighted average.
- CAPM
- Ke = Rf + β × (Rm − Rf)
- (Rm − Rf) is the market risk premium. Ke is the required return.
- Security market line
- Required return = Rf + β × (Rm − Rf)
- Same equation as CAPM, plotted against beta. Intercept is Rf; slope is the market risk premium.
Quick revision
- Fundamental analysis studies economy, industry and company; technical analysis studies price and volume.
- Expected return = Σ (probability × return).
- Standard deviation is the square root of variance, and it measures total risk.
- Bond value = present value of interest payments + present value of redemption value, discounted at the required return.
- Zero-coupon bond value = redemption value ÷ (1 + r)ⁿ.
- Constant growth model: P₀ = D₁ ÷ (k − g), valid only when k > g.
- D₁ = D₀ × (1 + g).
- Dow Theory describes primary, secondary and minor trends in the market.
- Weak form efficiency says past prices cannot predict future prices; semi-strong adds public information; strong adds all information including private.
- CAPM: Expected return = Rf + β × (Rm − Rf).
- Beta measures systematic risk, which diversification cannot remove.
- Diversification reduces unsystematic risk only.
Common mistakes
- Saying technical analysis studies the company's financial statements. Fix: Remember: technical looks at prices and volume only. Financial statements belong to fundamental analysis.
- Writing intrinsic value and market price as the same thing. Fix: Intrinsic value is your estimate of worth. Market price is what the share trades at. The gap between them drives the decision.
- Taking the simple average of returns when probabilities are given Fix: If probabilities are given, always use the weighted sum Σ p×R.
- Forgetting to take the square root, so variance is reported as standard deviation Fix: Write σ² and σ on separate lines. Variance is in squared percent; standard deviation is in percent.
- Using the market price or the required return to calculate the annual interest. Fix: Interest is always coupon rate × face value. The required return is used only for discounting.
- Adding the redemption value in every year, or forgetting to add it in the last year. Fix: Treat interest as an annuity for n years and the redemption value as a single sum at year n.
- Using D0 instead of D1 in Gordon's model Fix: Check the wording. If it says 'has just paid' or 'last dividend', multiply by (1 + g) first.
- Forgetting to discount the sale price in the DDM Fix: Discount the expected price at year n by (1 + ke)ⁿ, the same way as the dividend of that year.
- Mixing up support and resistance Fix: Support is the floor under falling prices. Resistance is the ceiling over rising prices.
- Treating Dow Theory trends as one trend Fix: Always name all three: primary, secondary and minor, with duration and role.
Exam tips
- Learn the comparison of fundamental and technical analysis as a five-point list. It is the most likely written question on this topic.
- Always include economy, industry and company when you explain fundamental analysis.
- Link each efficiency form to the method it challenges. This shows depth beyond definitions.
- Write a short conclusion on combining the approaches. ICSI-style answers reward a clear closing line.
- Keep short notes to about one third of a page. Use headings for each approach and bullet points for tools.
- Write the table in full. Marks are given for each step, so a correct method with a small arithmetic slip still scores.
- Learn the systematic and unsystematic lists with one example each. Theory questions often ask for the difference with examples.
- State the formula before substituting. Add a one-line conclusion naming the less risky or preferred security.