PEG Ratio Explained: When a High PE Can Still Be Cheap
The PEG ratio divides a stock’s price to earnings ratio by its expected earnings growth rate, expressed as a plain number. A stock at a PE of 30 with expected earnings growth of 25 percent has a PEG of 1.2. The point of the ratio is to judge whether a rich PE is justified by the growth behind it.
A rough convention treats PEG near or below 1 as reasonable and well above 2 as expensive. Treat that as a starting filter, not a verdict.
Everything about PEG rests on one input you cannot verify: the growth rate. Get that wrong and the ratio is worse than useless, because it looks precise.
The Formula and a Worked Example
PEG equals PE divided by the expected annual EPS growth percentage. Take an illustrative Indian consumer company at Rs 1,450 a share with trailing EPS of Rs 29, giving a PE of 50. If analysts expect 25 percent EPS growth, PEG is 50 divided by 25, which is 2.0. Expensive on this measure.
Now a midcap engineering firm at Rs 620 with EPS of Rs 31, so a PE of 20. If earnings are expected to compound at 22 percent, PEG is 0.91. On PE alone the consumer name looked better known and the engineering firm looked ordinary. On PEG the ranking flips.
How Sensitive the Answer Is
This is the part most articles skip. Keep the PE fixed at 30 and change only the growth assumption.
| Expected EPS growth | PEG at PE 30 | Reading |
|---|---|---|
| 30 percent | 1.0 | Fairly valued on this test |
| 25 percent | 1.2 | Slightly rich |
| 20 percent | 1.5 | Rich |
| 15 percent | 2.0 | Expensive |
| 10 percent | 3.0 | Very expensive |
A 10 point shift in a growth forecast triples the PEG. Since analyst forecasts for Indian midcaps and smallcaps often come from one or two brokerages, that shift is entirely plausible.
Where the Growth Number Comes From
- Trailing growth: actual EPS growth over the last three to five years, verifiable but backward looking
- Forward consensus: average of analyst estimates, forward looking but thinly covered for smaller companies
- Management guidance: useful context, naturally optimistic
- Your own estimate: built from volume, pricing, and margin assumptions, and the only one you fully control
State which one you used. A PEG built on trailing growth and a PEG built on forward consensus are different ratios wearing the same name.
When PEG Breaks Down
PEG assumes a stable, single growth rate, so it fails wherever earnings are lumpy. Cyclicals are the clearest case: a steel or sugar company coming off a depressed year can show 150 percent EPS growth, producing a PEG of 0.1 that means nothing except that the base year was terrible.
It also breaks with loss making companies, since there is no meaningful PE to start from, and with companies whose growth came from an acquisition rather than the underlying business.
What PEG Ignores Entirely
Debt, cash generation, and return on capital. Two firms can share a PE of 25 and 20 percent expected growth, giving both a PEG of 1.25, while one funds that growth from internal cash and the other from continuous borrowing and equity dilution. The second is a much worse holding, and PEG cannot see it.
The Dilution Trap
Growth in total net profit is not the same as growth in EPS. A company that raises equity repeatedly grows profit while EPS crawls, so always use per share numbers, and check the diluted EPS line rather than basic EPS.
Frequently Asked Questions
Should the growth rate be entered as 25 or 0.25?
Use the whole number, so 25 for 25 percent growth. Entering 0.25 gives a PEG of 120 instead of 1.2, which is a surprisingly common spreadsheet mistake.
How many years of growth should PEG use?
Two to three years of expected EPS growth is the usual practice, because forecasts beyond that are guesses. Using a single year makes PEG jump around with one-off items.
Is a PEG below 1 a buy signal?
No. It is a prompt to check why, since a low PEG often comes from an unsustainable growth forecast, a depressed base year, or a market that has spotted a risk you have not. Verify the earnings quality before treating it as cheap.
Can I use PEG for banks and NBFCs?
You can, with care, since lending profits grow with the loan book and credit costs can turn suddenly. Pair it with asset quality data such as gross non performing assets and provision coverage before drawing any conclusion.
What is a dividend adjusted PEG?
Some analysts add the dividend yield to the growth rate before dividing, which lowers PEG for high payout companies. It helps when comparing a slow growing dividend payer against a faster grower that pays nothing.
Key Takeaways
- PEG equals PE divided by expected EPS growth in percent.
- Below 1 is a filter to investigate, not a signal to buy.
- A small change in the growth estimate moves PEG a lot.
- It fails for cyclicals, loss makers, and acquisition led growth.
- PEG ignores debt, cash flow, and return on capital, so check those separately.
