2 Important Ratios You Should Look at Before Buying Any Stock

Canadian National Railway (TSX:CNR)(NYSE:CNI) is a great example of a stock that trades at very modest multiples and that could be a solid investment to make today.

| More on:

Valuations for a stock can get out of control sometimes. However, over the long term, investors can expect to see things stabilize and return to more normal levels.

A good example of this is the cannabis industry, where valuations have often become obscene, with promises of future growth being enough for many investors to forgive many other shortcomings, including poor market share and little hope for profitability in the imminent future.

It’s not surprising that we’ve seen some of those highly priced stocks fall in value recently. Investors can, however, protect themselves from big corrections in share price by simply taking a look at a couple of important ratios that will quickly help identify if there is a problem with a stock’s value.

Price-to-earnings ratio

The first ratio is a very common one, price-to-earnings (P/E). It’s an easy one to calculate and serves as a very good benchmark when comparing other companies.

It is calculated by taking the current stock price and dividing it by the earnings per share (EPS) that the company has generated over the past four quarters.

As it involves price, it has the opportunity to fluctuate very quickly, but can help you make a quick assessment of whether a stock is overpriced or not.

Let’s look at Canadian National Railway (TSX:CNR)(NYSE:CNI) as an example. Over the past four quarters, the company has generated profits of $4.4 billion.

If we divide that by 725 million shares, that gives us an EPS of a little over $6.1. With the stock price around $124, its P/E is a little more than 20.

Value investors might sometimes target a P/E that’s 15 or less, although 20 isn’t a very high multiple, especially since CN Rail has shown some good growth over the years.

Generally, a P/E of 15 or less is most suitable for stocks that don’t have a lot of growth. Tech stocks may often trade at 30 times their earnings, or even higher.

But if you see a stock that’s trading more than 100 times its earnings, it’s something that warrants further investigation. It could be that the company has had a bad quarter dragging down its numbers over the past year, or it could be a sign that the stock has simply gotten too expensive.

If a company doesn’t have any earnings, then obviously a P/E ratio won’t be very helpful. This is where we can move on to the next multiple:

Price-to-sales multiple

Using a price-to-sales (P/S) multiple is another valuable tool in assessing value. This calculation involves taking the company’s market cap and dividing it by its sales over the past year.

If we go back to CN Rail, the stock has a value of around $89 billion. And over the past four quarters, sales have totaled $15 billion. This tells us that CN Rail’s P/S ratio is at around 5.9.

There’s a lot more variability here as to what’s acceptable, but generally, if you’re under a P/S of 10 then that’s good. Ideally, however, you’d like to see the multiple as low as possible.

Here again, it would’ve helped flag high-flying cannabis stocks that were trading more than 100 times their sales.

Bottom line

These multiples can help you get an idea of how much of a premium you’d be paying to own a stock today. It’s also helpful when comparing similar investments.

Ultimately, there are many other ways you can assess a company’s value, but these two ratios can, at a minimum, help you identify stocks which are grossly overvalued based on their recent performances.

Fool contributor David Jagielski has no position in any of the stocks mentioned. CN is a recommendation of Stock Advisor Canada.

More on Dividend Stocks

ETF stands for Exchange Traded Fund
Dividend Stocks

3 Canadian ETFs I’d Snap Up Right Now for My TFSA

These three high-quality Canadian ETFs are perfect for TFSAs, offering instant diversification to top stocks from around the world.

Read more »

how to save money
Dividend Stocks

The Best Stocks to Buy With $10,000 Right Now

Add these two TSX stocks to your self-directed investment portfolio if you’re seeking long-term buying opportunities in the current climate.

Read more »

coins jump into piggy bank
Dividend Stocks

How to Convert $25,000 in TFSA Savings Into Reliable Cash Flow

With $25,000 invested into Fortis (TSX:FTS) stock, you can get some cash flow in your TFSA.

Read more »

dividends can compound over time
Dividend Stocks

2 Dividend Stocks to Lock In Now for Decades of Passive Income

These two Canadian dividend stocks are both defensive and generate tons of cash flow, making them ideal for passive-income seekers.

Read more »

man looks surprised at investment growth
Dividend Stocks

If I Could Only Buy and Hold a Single Stock, This Would Be it

Brookfield (TSX:BN) is a very high-quality stock.

Read more »

ETF is short for exchange traded fund, a popular investment choice for Canadians
Dividend Stocks

The ETFs That Canadians Are Sleeping On (But Shouldn’t Be) Right Now

These three high-quality Canadian ETFs are perfect for investors in 2026, especially with increasing uncertainty and volatility in markets.

Read more »

boy in bowtie and glasses gives positive thumbs up
Dividend Stocks

My Top Pick for Immediate Income? This 7.6% Dividend Stock

Slate Grocery REIT is an impressive high-yield option for investors seeking reliable income from defensive retail.

Read more »

TFSA (Tax-Free Savings Account) on wooden blocks and Canadian one hundred dollar bills.
Dividend Stocks

CRA: How to Use Your TFSA Contribution Limit in 2026

After understanding the CRA thresholds, the next step is to learn the core strategies in using your TFSA contribution limit…

Read more »