A valuation multiple is meaningless in isolation. Telling someone that a company has a P/E ratio of 15x is like saying a person is 6 feet tall—it only tells you something useful if you know the average height of the population. In relative valuation, that "population" is the Comparable Group (or "Comps Set") .

The standard way to estimate a company's value is to find publicly traded companies that most closely match the target company . This is much like how a real estate agent determines a home's value by looking at similar houses that recently sold in the same neighborhood . If your "comps" are bad, your valuation will be bad. As analyst Bridger Pennington warns: "If your comparables aren’t truly comparable, the multiples can mislead you" .

The Criteria for a Perfect Match

Finding the right peer group requires careful research. You aren't just looking for any company in the same broad sector; you are looking for direct competitors that mirror the target's operations as closely as possible . Analysts typically look for four key similarities:

1. Industry and Business Model

The companies must operate in the same space. If you are valuing a mid-sized online fashion retailer, you wouldn't compare it to Walmart (a massive general retailer) or FedEx (a logistics company). Instead, you would look at peers like Revolve Group or ThredUp . You want companies that face the same market risks, customer trends, and regulatory environments.

2. Size (Market Capitalization)

Size matters. Larger companies often command higher multiples because they have greater market share, more established management teams, and better "resilience" to economic shocks . A massive industry leader like JPMorgan Chase will naturally trade at different multiples than a small regional bank with three branches .

3. Growth Rates

Investors pay a premium for growth. If Company A is growing its revenue at 20% per year and Company B is growing at 2%, Company A should have a higher P/E ratio . When building a comp set, try to find companies with similar "forward-looking" growth prospects.

4. Profitability and Margins

Efficiency is a key driver of value. Analysts look at operating margins—how effectively a company turns sales into profit . A company with a 20% profit margin is fundamentally more valuable than one with a 5% margin, even if they have the same total revenue.

Case Study: Analyzing Eastman Chemical

To see this in action, let's look at a real-world example of a "Comps Table" for Eastman Chemical (EMN), a diversified chemical firm. An analyst would pull data for its closest rivals to see where Eastman fits .

Company	Market Cap ($B)	P/E Ratio (TTM)	P/B Ratio (TTM)	Net Margin
Eastman Chemical (Target)	$13.31	16.95x	2.33x	7.6%
Dow Chemical	$48.83	7.35x	2.73x	11.8%
DuPont	$33.29	21.89x	1.27x	9.0%
Air Products & Chemicals	$52.52	24.35x	3.89x	19.1%
Huntsman Chemical	$7.44	6.56x	1.73x	13.2%
Average of Peers	$35.52	15.04x	2.41x	13.3%

Data adapted from

What does this table tell us?

Relative Pricing: Eastman’s P/E of 16.95x is slightly higher than the peer average of 15.04x. This suggests the market might be pricing in higher expectations for Eastman's future growth compared to some of its cheaper rivals like Huntsman .
Efficiency Gap: Eastman has the lowest net margin (7.6%) in the group. This is a "red flag." It indicates that Eastman is less efficient at turning sales into profit than its larger peers like Air Products (19.1%) .
Size Discount: Eastman is one of the smaller companies in this set. This might explain why it hasn't captured the "economies of scale" that allow Dow or DuPont to have higher margins .

The Challenge of Private Companies

Valuing a private company is significantly harder because they don't provide public financial reports . In these cases, analysts use "Comparable Company Analysis" (CCA) by looking at public peers and then applying "adjustments" .

Because private company shares are harder to sell (you can't just click "sell" on an app), analysts often apply an Illiquidity Discount—typically reducing the valuation by 20% to 30% compared to public peers .

The "X" (Twitter) Example:
When Elon Musk took Twitter private for $44 billion, it became a private entity. To value it later, investors like Fidelity had to look at public peers like Meta (Facebook) and Snap . Because Meta and Snap were performing well while Twitter's ad revenue dropped by 50%, Fidelity "marked down" the value of its Twitter holdings by over 70% . This shows how relative valuation works even when a company's books are closed—you look at the "weather" affecting the neighbors to guess what's happening inside the house.

Step-by-Step: How to Build Your Comp Set

Start Broad: Use a stock screener to find all companies in the same GICS (Global Industry Classification Standard) sector.
Filter by Size: Narrow the list to companies within a similar market cap range (e.g., $1B to $5B).
Refine by Geography: Ensure the companies operate in similar markets. A tech company in Silicon Valley faces different costs and risks than one in emerging markets.
Check the "Business Mix": Read the "Business Description" in the 10-K filing. Does the company actually make money the same way your target does?
Select 5-10 Peers: You want enough companies to create a meaningful average, but not so many that you include "low-quality" matches that skew the data .

Summary Checklist for Peer Selection

Are they in the same industry?
Is the revenue size comparable?
Do they have similar growth prospects?
Are their profit margins in the same ballpark?
Do they operate in the same geographic regions?

Once you have your group and your ratios, you are ready for the final step: crunching the numbers to find the target's value.