How to Read a P/E Ratio Without Misleading Your Clients
A tech stock at 40x forward earnings sits in your client's RRSP next to a Big Five bank trading at 11x trailing. One of them might be mispriced. Both might be fine. The number alone tells you nothing.
The P/E ratio is the most quoted valuation metric in finance and the most misused. It divides share price by earnings per share, giving you a multiple. The error is treating that multiple as a verdict. A high P/E doesn't mean overvalued. A low one doesn't mean cheap. The metric works only when you know which earnings figure you're using, which peer group you're comparing against, and whether the company's earnings are real or dressed up.
Trailing vs. Forward: Pick One and Label It
Trailing P/E uses the past 12 months of reported earnings. Forward P/E uses analyst projections for the next 12 months. The S&P/TSX Composite typically trades between 14x and 18x on a forward basis, but that average hides everything. Canadian banks cluster around 13x to 15x. SaaS companies in Toronto trade above 40x.
If you quote a P/E to a client, name which version you're using in the same sentence. "The stock trades at 22x forward earnings" is clear. "The stock trades at 22x" leaves the client guessing whether that's last year's number or next year's hope. In volatile markets, forward P/Es lag reality because analysts are slow to cut estimates. A forward 15x in a softening economy is not the same as a trailing 15x with stable results behind it.
Compare Within the Sector, Not Across It
A P/E of 15x means different things depending on capital intensity and growth expectations. Utilities are stable, regulated, and slow-growing, 15x is normal. Junior mining explorers burn cash and have no earnings to speak of, so P/E is useless and you use Price-to-Sales or Price-to-Book instead.
The "Canadian discount" exists because the TSX is weighted toward Financials and Energy, both cyclical and capital-heavy. The S&P 500 is loaded with mega-cap tech. The TSX holds a much higher weight in banks and oil companies, while the S&P 500 holds a much higher weight in software and semiconductors. Compare Shopify to Adobe. Compare TD to JPMorgan. Don't compare Shopify to TD.
Flip It to Compare Against Bonds
The earnings yield is the P/E ratio inverted: earnings divided by price. A stock at 20x has an earnings yield of 5%. That yield can be compared directly to the 10-year Government of Canada bond. If the bond yields 3.5% and the stock yields 5%, the stock offers a 1.5% premium for taking on equity risk. If that spread narrows or inverts, it tells you something about how the market is pricing growth or safety.
As the Bank of Canada raised rates through 2022 and 2023, equity P/E multiples compressed because future earnings became worth less in present-value terms. The same mechanic runs in reverse when rates fall.
Use PEG When Growth Matters
A P/E of 25 looks expensive until you see the company is growing earnings at 50% annually. The PEG ratio divides the P/E by the earnings growth rate. A PEG below 1.0 suggests the stock is cheap relative to its growth. A stock at 25x growing at 50% has a PEG of 0.5. One at 15x growing at 5% has a PEG of 3.0. The second is more expensive on a growth-adjusted basis.
PEG only works when growth is real and sustainable. Analysts in 2020 and 2021 priced in growth rates that never materialized, and the PEG ratios looked attractive right up until they didn't.
Watch for Earnings Quality
Companies can inflate the "E" through share buybacks, which reduce the share count and mechanically lift EPS without improving the business. Adjusted earnings strip out one-time costs, restructuring charges, and "non-recurring" expenses that recur every year. GAAP earnings include everything. A stock at 18x adjusted but 24x GAAP is telling you something about the quality of those results.
For cyclical names like Nutrien or Suncor, P/E ratios are often lowest at the cycle peak, when earnings are unsustainably high, and highest at the trough. A resource stock at 8x might be expensive if commodity prices are about to collapse. One at 18x might be cheap if it's coming off a bottom.
The ratio is a starting question. What you do with the answer depends on everything the number doesn't show you.
A tech stock at 40x forward earnings sits in your client's RRSP next to a Big Five bank trading at 11x trailing. One of them might be mispriced. Both might be fine. The number alone tells you nothing.
The P/E ratio is the most quoted valuation metric in finance and the most misused. It divides share price by earnings per share, giving you a multiple. The error is treating that multiple as a verdict. A high P/E doesn't mean overvalued. A low one doesn't mean cheap. The metric works only when you know which earnings figure you're using, which peer group you're comparing against, and whether the company's earnings are real or dressed up.
Trailing vs. Forward: Pick One and Label It
Trailing P/E uses the past 12 months of reported earnings. Forward P/E uses analyst projections for the next 12 months. The S&P/TSX Composite typically trades between 14x and 18x on a forward basis, but that average hides everything. Canadian banks cluster around 13x to 15x. SaaS companies in Toronto trade above 40x.
If you quote a P/E to a client, name which version you're using in the same sentence. "The stock trades at 22x forward earnings" is clear. "The stock trades at 22x" leaves the client guessing whether that's last year's number or next year's hope. In volatile markets, forward P/Es lag reality because analysts are slow to cut estimates. A forward 15x in a softening economy is not the same as a trailing 15x with stable results behind it.
Compare Within the Sector, Not Across It
A P/E of 15x means different things depending on capital intensity and growth expectations. Utilities are stable, regulated, and slow-growing, 15x is normal. Junior mining explorers burn cash and have no earnings to speak of, so P/E is useless and you use Price-to-Sales or Price-to-Book instead.
The "Canadian discount" exists because the TSX is weighted toward Financials and Energy, both cyclical and capital-heavy. The S&P 500 is loaded with mega-cap tech. The TSX holds a much higher weight in banks and oil companies, while the S&P 500 holds a much higher weight in software and semiconductors. Compare Shopify to Adobe. Compare TD to JPMorgan. Don't compare Shopify to TD.
Flip It to Compare Against Bonds
The earnings yield is the P/E ratio inverted: earnings divided by price. A stock at 20x has an earnings yield of 5%. That yield can be compared directly to the 10-year Government of Canada bond. If the bond yields 3.5% and the stock yields 5%, the stock offers a 1.5% premium for taking on equity risk. If that spread narrows or inverts, it tells you something about how the market is pricing growth or safety.
As the Bank of Canada raised rates through 2022 and 2023, equity P/E multiples compressed because future earnings became worth less in present-value terms. The same mechanic runs in reverse when rates fall.
Use PEG When Growth Matters
A P/E of 25 looks expensive until you see the company is growing earnings at 50% annually. The PEG ratio divides the P/E by the earnings growth rate. A PEG below 1.0 suggests the stock is cheap relative to its growth. A stock at 25x growing at 50% has a PEG of 0.5. One at 15x growing at 5% has a PEG of 3.0. The second is more expensive on a growth-adjusted basis.
PEG only works when growth is real and sustainable. Analysts in 2020 and 2021 priced in growth rates that never materialized, and the PEG ratios looked attractive right up until they didn't.
Watch for Earnings Quality
Companies can inflate the "E" through share buybacks, which reduce the share count and mechanically lift EPS without improving the business. Adjusted earnings strip out one-time costs, restructuring charges, and "non-recurring" expenses that recur every year. GAAP earnings include everything. A stock at 18x adjusted but 24x GAAP is telling you something about the quality of those results.
For cyclical names like Nutrien or Suncor, P/E ratios are often lowest at the cycle peak, when earnings are unsustainably high, and highest at the trough. A resource stock at 8x might be expensive if commodity prices are about to collapse. One at 18x might be cheap if it's coming off a bottom.
The ratio is a starting question. What you do with the answer depends on everything the number doesn't show you.
Sources
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