P/E = Market Price per Share divided by EPS — measures how much investors pay per rupee of earnings Trailing P/E uses last 12 months actual EPS; Forward P/E uses next 12 months projected EPS P/E is useless for loss-making companies — use EV/Sales or P/BV instead
What is the Price-to-Earnings (P/E) Ratio?
The Price-to-Earnings (P/E) ratio is the most widely used equity valuation metric in the world. It tells you how much the market is willing to pay for every rupee of a company's earnings. Formula: P/E = Market Price per Share ÷ Earnings per Share (EPS). If a stock trades at ₹500 and its EPS is ₹25, the P/E ratio is 20x — meaning investors pay ₹20 for every ₹1 of annual earnings. For NISM Series XV candidates, understanding P/E deeply — including its limitations — is non-negotiable.
Trailing P/E vs Forward P/E
There are two primary versions of P/E that appear on the NISM XV exam:
Trailing P/E (Historical)
Uses actual reported EPS from the most recent 12 months (TTM — Trailing Twelve Months). Formula: Trailing P/E = Current Market Price ÷ EPS (last 12 months). Uses real numbers, but reflects the past not the future.
Forward P/E (Projected)
Uses analysts' projected EPS for the next 12 months. Formula: Forward P/E = Current Market Price ÷ Expected EPS (next 12 months). Most research reports in India use forward P/E for target-setting. If a company is expected to grow earnings significantly, forward P/E will be lower than trailing P/E — making the stock appear cheaper on a forward basis.
What Does P/E Tell a Research Analyst?
P/E is a relative signal, not an absolute one. A P/E of 30x is not inherently expensive — it depends on the sector, the company's growth rate, and the broader market P/E. Research analysts use P/E three ways: (1) compare a stock against its own historical P/E range, (2) compare against sector peers, and (3) compare against the broader market index. A company trading at a premium to peers may be genuinely superior — better margins, stronger growth, lower risk — or may simply be overvalued.
Sector P/E Benchmarks in India
There is no universal "good" P/E — it is always relative. Approximate Indian sector benchmarks:
- FMCG: 40–60x (premium for predictable cash flows and brand moats)
- IT services: 25–35x (capital-light, high margins, dollar revenue)
- Banking / NBFC: 10–20x (P/E less useful here; P/BV preferred)
- Auto / Capital Goods: 15–25x (cyclical; P/E fluctuates widely)
- Pharma: 20–35x (growth but regulatory risk)
- PSU companies: 5–15x (state ownership, dividend focus)
P/E Limitations Research Analysts Must Know
P/E is the most used but also the most misused metric. Key limitations:
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- Cannot be used for loss-making companies: Negative EPS produces a meaningless negative P/E. Use EV/Sales or P/BV instead.
- Distorted by one-time items: A large non-recurring gain inflates EPS and depresses P/E artificially. Always normalise EPS by excluding one-time items.
- Ignores capital structure: P/E does not reflect how much debt a company carries. EV/EBITDA is better for capital structure-neutral comparisons.
- Earnings can be managed: Aggressive accounting can inflate reported EPS. Analysts cross-check P/E against cash flow multiples (P/CFO) to detect manipulation.
PEG Ratio: P/E Adjusted for Growth
The PEG ratio fixes P/E's biggest blind spot — it ignores the growth rate. PEG = P/E ÷ Expected Earnings Growth Rate (%). A stock with P/E of 30x and expected EPS growth of 30% has PEG = 1.0 (fairly valued). A stock with P/E of 20x and growth of 8% has PEG = 2.5 (expensive relative to growth). Rule of thumb: PEG < 1 = potentially undervalued; PEG 1–2 = fairly valued; PEG > 2 = expensive.
NISM XV Exam Practice Questions
Q1. Company A P/E = 15x, Company B P/E = 35x, same sector. Which is necessarily cheaper?
Answer: Neither necessarily. Company B may have higher P/E because it is growing earnings at 40%/year vs Company A at 5%. PEG ratio gives a more complete picture than P/E alone.
Q2. Why is P/E ratio not useful for a loss-making company?
Answer: Negative EPS divided into market price produces a meaningless negative P/E. Analysts use EV/Sales, EV/Gross Profit, or Price/Book for loss-making companies instead.
Q3. What is the difference between trailing P/E and forward P/E?
Answer: Trailing P/E uses actual reported EPS from the last 12 months. Forward P/E uses analysts' consensus EPS estimate for the next 12 months. Research reports use forward P/E for target setting since investing is about future earnings.
Related: DCF Valuation → | Reading a P&L Statement → | NISM XV Full Study Hub →