How to Do a Sum-of-the-Parts Valuation: Step-by-Step Guide

Quick answer

To do a sum-of-the-parts valuation, split the company into its business segments and major assets, value each part with the method that suits it, and add the values together. Then subtract capitalized corporate costs, net debt and other claims, and divide by the diluted share count. The result is an estimate of what the shares would be worth if each business were valued on its own.

The method is most useful for companies that own businesses with very different economics, such as a slow-growing industrial unit next to a fast-growing software unit, or an operating company that also holds a listed stake in another company. One multiple applied to the whole group blurs those differences. This guide walks through the full build with one hypothetical company.

Key takeaways

A sum-of-the-parts valuation values each segment or asset separately, adds them up, subtracts corporate costs and net claims, and divides by diluted shares.
Segment revenue and profit come from the segment note in the 10-K, so start there rather than from the headline income statement.
Each part needs a valuation method that fits it: an earnings multiple for an operating business, a market price for a listed stake, an appraisal or book value for real estate.
Capitalize unallocated corporate costs and apply tax to any asset that would be sold at a gain, or the total will overstate what owners could actually receive.
A gap between the sum of the parts and the share price only matters if something, such as a spin-off, sale or buyback, is likely to close it.

Table of contents

What you need
Step 1: Map the parts from the filings
Step 2: Pick a profit measure for each segment
Step 3: Choose a valuation method for each part
Step 4: Value each operating segment
Step 5: Subtract capitalized corporate costs
Step 6: Add the non-operating assets
Step 7: Bridge from enterprise value to equity per share
Step 8: Run a range and test the largest inputs
Step 9: Identify what would close the gap
Common mistakes
Where this goes wrong
The bottom line

What you need

The latest 10-K and any 10-Q filed since. The segment note in the financial statements is the core input. The guide on searching SEC EDGAR filings shows how to pull them.
An enterprise value build for the whole company, so you know the debt, cash and other claims. See how to calculate enterprise value.
A short list of comparable listed companies for each segment, with their EV/EBITDA or other multiples.
Market prices for any listed stakes the company holds.
A spreadsheet with one row per part and a column for the source of each figure.

Step 1: Map the parts from the filings

Start with Item 1 of the 10-K, which describes the business under Item 101 of Regulation S-K, and then go to the segment note in the financial statements under Item 8. The segment note lists each reportable segment with its revenue and a profit measure, and reconciles the segment totals to consolidated results. That reconciliation shows the unallocated corporate costs you will need in Step 5.

Then list everything that is not in an operating segment: equity-method investments, listed stakes, real estate not used in operations, tax assets, and businesses held for sale. These often sit in the investments note, the property note or the discontinued operations note. A 10-K is due 60 days after fiscal year end for large accelerated filers, 75 days for accelerated filers and 90 days for all other registrants, so check the 10-Qs and 8-Ks filed since for asset sales or acquisitions that change the map. The 10-Q guide for special situations shows where these notes sit in a quarterly filing.

Step 2: Pick a profit measure for each segment

Use the profit measure the company reports for its segments, and convert it to a common basis if you can. Many companies report segment operating income. If the note also gives segment depreciation and amortization, add it back to get segment EBITDA, which lets you use EV/EBITDA multiples from comparable companies.

Check three things before moving on:

Allocation. Some companies push corporate costs into the segments; others keep them in a separate line. Read the accounting policy for segments so you do not count overhead twice or not at all.
Inter-segment sales. Revenue between segments is eliminated in the consolidated figures. Use external revenue when you compare a segment with peers.
Period. Use trailing twelve months or the latest fiscal year for every segment. Mixing periods distorts the total.

Step 3: Choose a valuation method for each part

Each part gets the method that fits how a buyer or the market would price it on its own.

Part	Typical method	Where the input comes from
Mature operating segment	EV/EBITDA or EV/EBIT from listed peers	Segment note, peer filings
Fast-growing or loss-making segment	EV/sales from listed peers	Segment note, peer filings
Listed stake in another company	Market price x shares held, less tax on gain	Investments note, market quote
Unlisted stake or joint venture	Share of earnings x peer multiple, or book value	Equity-method note
Surplus real estate	Appraisal, recent comparable sales, or book value	Property note, local sale records
Cash-generating runoff business	Discounted cash flow of the remaining flows	Segment note, MD&A

Use a range of multiples for each segment, not one figure. A low, base and high case built from the spread of peer multiples gives you a sense of how much the answer depends on judgment. The price-to-sales explainer covers when a sales multiple is appropriate.

Step 4: Value each operating segment

Multiply each segment's profit measure by its chosen multiple. The result is the enterprise value of that segment, before corporate costs and before debt.

Be honest about fit. A segment that is smaller, slower or more cyclical than its listed peers deserves a lower multiple than their median.

Step 5: Subtract capitalized corporate costs

The segment reconciliation usually shows a line called corporate, unallocated or eliminations. It covers head office, the board, public company costs and some shared services. Those costs are real, and they would not all disappear if the businesses were separated, because each standalone company would need some of its own.

Capitalize the annual cost at the blended multiple of the segments and subtract it. If you expect a separation to remove part of the cost, show that as a separate scenario, not as your base case.

Step 6: Add the non-operating assets

Now add the parts that do not earn segment profit.

Listed stakes: shares held times the current market price. If the company would have to sell the stake to realize the value, subtract tax on the gain over its tax basis, which is often disclosed in the income tax or investments note.
Unlisted stakes: use the share of the investee's earnings times a peer multiple, or the carrying value if the earnings are small or erratic.
Surplus real estate: use an appraisal or recent comparable sales if available, and book value as a floor-level fallback.

Do not add an asset whose income is already in a segment's EBITDA. That counts the same value twice.

Add the segment values and non-operating assets, subtract capitalized corporate costs, then subtract the same claims you would in any enterprise value build: debt, preferred stock, noncontrolling interest and debt-like items such as an unfunded pension. Add back cash and liquid investments. Divide by fully diluted shares.

Line	Company A ($ millions)
Operating segments	1,910
Less capitalized corporate costs	(200)
Plus listed stake, after tax	200
Plus surplus land	150
Less net debt	(500)
Less pension deficit and noncontrolling interest	(70)
Equity value	1,490
Per share (100 million diluted shares)	$14.90

At a price of $10.00, Company A trades about 33% below this base-case sum of the parts (illustrative). The net cash per share explainer covers the cash and debt side of this bridge in more detail.

Step 8: Run a range and test the largest inputs

A single number hides how fragile the result is. Build a low, base and high case, changing the multiples, the real estate value and the tax assumption together.

Then ask which single input moves the answer most. Usually it is the multiple on the largest segment. If one turn of that multiple moves the per-share value by more than the discount you think you see, the discount is less certain than it looks.

Step 9: Identify what would close the gap

A sum of the parts above the share price is a description, not a reason the price will change. Many multi-business companies trade below their parts for years. Look for a mechanism and a date:

If the company has announced a spin-off, the Form 10 will show standalone financials for the business being separated. See what a Form 10 is and spin-off investing.
If an activist has filed a 13D asking for a break-up, the filing states its plans. See what a 13D filing is.
If the company is selling a division, the price paid tests your multiple directly.
If the company is buying back stock below your estimate, each repurchase raises value per remaining share.
If none of these apply, the gap may persist, and the honest conclusion is that the parts are cheap without a catalyst.

Dombey's published research pairs this kind of break-up analysis with the dated event that could close the gap; see the research archive. Record the result, its range and the expected catalyst date in a dated investment thesis.

Common mistakes

Using the consolidated multiple for every segment. That defeats the purpose of the exercise and returns roughly the current market value.
Ignoring corporate costs. Leaving out head office expense inflates the total, often by several percent of equity value.
Counting an asset twice. An equity-method stake whose income sits inside segment EBITDA should not also be added as a separate asset.
Valuing stakes before tax. A sale at a large gain triggers tax. Only a tax-free separation avoids it, and that is not certain.
Choosing peers that flatter. Picking the highest-multiple peer for each segment produces a large discount that no buyer would pay.
Forgetting separation costs. Separated businesses lose shared purchasing, shared IT and shared sales teams. Standalone costs can be higher than the segment note suggests.

Where this goes wrong

Segment data is limited. Companies choose their own segment boundaries and profit measures, and allocation of shared costs can make a weak segment look stronger than it would be alone. Peer multiples move with the market, so a sum of the parts built at a high point for one industry can shrink quickly. Separation itself costs money: advisory fees, new systems, new boards and possibly tax, and the parts may not trade where you assumed once they stand alone. The method also says nothing about timing. A discount can widen before it closes, and the capital you commit has an opportunity cost while you wait. Use the result as a range and a set of questions for the next filing, not as a fixed value.

The bottom line

A sum-of-the-parts valuation values each business and asset on its own terms, then subtracts corporate costs and the claims ahead of common shareholders. The segment note in the 10-K is the starting point, and each part needs a method and a peer group that fits it. Run a low, base and high case, because the multiple on the largest segment usually drives the answer. A gap between the parts and the price matters only when a spin-off, sale, activist or buyback gives it a way to close.

Frequently asked questions

What is a sum-of-the-parts valuation?

It is a way to value a company with several distinct businesses by valuing each one on its own and adding the results. You then subtract corporate costs, debt and other claims to reach an equity value per share. Analysts also call it SOTP or break-up analysis.

When should I use a sum-of-the-parts valuation?

Use it when a company owns businesses that grow at different rates, carry different risks or would trade at different multiples as standalone companies. Conglomerates, holding companies, companies with large stakes in other businesses, and companies planning a spin-off or divestiture are the usual cases.

Where do I find segment data for a sum-of-the-parts valuation?

The segment note in the financial statements of the 10-K and 10-Q gives revenue and a profit measure for each reportable segment. Item 1 of the 10-K describes the businesses. Investor presentations and the MD&A section often add detail such as segment EBITDA or capital spending.

What is a conglomerate discount?

It is the gap that often appears when a multi-business company trades below the sum of its parts. Common explanations are corporate overhead, capital moving from strong units to weak ones, complexity that makes the company harder to analyze, and tax costs of separating the businesses. The discount can last for years.

How do I value corporate overhead in a sum-of-the-parts?

Take the unallocated corporate expense from the segment note reconciliation and apply a multiple to it, usually the blended multiple of the segments. The result is subtracted from the total. Leaving it out treats a real cost as if it would disappear.

Should I apply taxes to a sum-of-the-parts valuation?

Apply tax to any part you value on the assumption it would be sold, such as an investment stake or real estate held well above its tax basis. A tax-free spin-off may avoid that cost, but a sale usually does not. State your assumption in the model.

Is a sum-of-the-parts valuation reliable?

It is only as good as the multiples and segment figures you use. Small changes in the multiple for the largest segment can move the result a great deal, so always run a range. Treat the output as a range of reasonable values, not a price target.

Sources

Article details

By James Whitfield, Head of Equity Research, Dombey Capital

Published October 8, 2026 · 9 min read · Valuation