PEG Ratio
The PEG Ratio (Price/Earnings to Growth) adjusts the P/E ratio by the company's expected earnings growth rate, providing a more nuanced valuation that accounts for future growth potential.
A PEG below 1 is often interpreted as a signal that the stock may be undervalued relative to its growth trajectory, while a PEG above 1 may indicate that the market is pricing in growth that has already been fully recognised or even over-anticipated. The metric was popularised by investor Peter Lynch, who argued that a fairly valued stock should have its P/E roughly equal its earnings growth rate — hence a PEG of 1.
In the Indian market, PEG is most useful for identifying high-quality growth companies where a superficially high P/E is justified by genuinely rapid earnings expansion. During the mid-cap rally of 2017, several small and mid-cap consumer goods and specialty chemicals companies traded at P/Es of 40–60x. For those whose earnings were growing at 25–35% annually, the PEG ratios were in the range of 1.5–2x — not cheap, but not as egregiously valued as the raw P/E suggested. Investors who used only P/E might have misjudged the valuation.
The denominator — earnings growth rate — is where most analytical debate occurs. Analysts use different inputs: the historical compound annual growth rate of EPS over 3–5 years, the consensus forward earnings growth estimate, or the expected 5-year growth rate. Each produces a different PEG ratio. Indian companies often show lumpy earnings growth due to currency effects, commodity cycles, or one-off tax provisions, so smoothing the growth rate is necessary for a meaningful PEG calculation.
Fast-growing new-age companies that listed in India between 2021 and 2023 — such as Zomato, Nykaa, and Paytm — initially had no earnings at all, making PEG inapplicable. Some analysts stretched the concept to use revenue growth or gross profit growth in the denominator, but these modifications are non-standard and should be treated with caution.
Like all single-number metrics, PEG is best used as a screening tool rather than a standalone verdict. A company with a low PEG driven by very high projected growth deserves further scrutiny: is the growth assumption realistic, recurring, and based on durable competitive advantages, or is it an analyst's optimistic extrapolation of a temporarily favourable environment?