A Buffett Blueprint: How Robert Hagstrom Identifies Strong, Undervalued Stocks

Learn how Robert Hagstrom applies Warren Buffett’s value investing principles to find strong, undervalued stocks. Explore AAII’s Buffett Hagstrom screen and its 13.8% annualized return since 1998.

This week, we cover the stock-picking strategy of Warren Buffett and give you a list of stocks that currently pass our screen based on Robert Hagstrom’s extensive writings about Buffett’s approach. Possibly no other investor today is as strongly associated with the basic principles of fundamental investing as Buffett.

AAII has adapted Hagstrom’s research into a screen that returns 30 companies based on several fundamental and financial strength metrics. The screen finds companies with a history of strong returns to shareholders, positive gross operating income and positive free cash flow. As of September 30, 2025, AAII’s Buffett Hagstrom screen has an annualized gain of 13.8% since inception in 1998, compared to the S&P 500 index’s return of 7.3% over the same period.

Developing a Buffett Approach

While some critics feel that Buffett’s strategy cannot be duplicated, Hagstrom disagrees. He has authored several popular books that highlight Buffett’s core investing principles. In “The Essential Buffett: Timeless Principles for the New Economy” (Wiley, 2007), Hagstrom argues that it is possible to duplicate Buffett’s approach within your personal area of expertise. He presents the strategy through an accessible series of questions that should be explored with any potential investment. The approach demands that you:

• Analyze a stock as a business,

• Demand a margin of safety for each purchase,

• Manage a focused portfolio, and

• Protect yourself from the speculative and emotional forces of the market.

Buffett feels that speculators are primarily concerned with a company’s stock price, while investors first focus on how the business is doing. Buffett is a firm believer that knowledge helps to increase investment return and reduce risk.

It is also important to keep one’s emotions in check. We should not let our emotions override our good judgment. Every person must take their own psychology into account. Some losses are inevitable when it comes to investing, so if you cannot emotionally handle the volatility, then you should consider a more conservative investing style.

12 Buffett Principles

Hagstrom identifies 12 basic Buffett principles that a company should possess to be considered for purchase. Not all of Buffett’s purchases display all these tenets, but as a group, the principles help to establish a reasonable approach to selecting stocks. The tenets cover both qualitative and quantitative business elements. These are used to create the Buffett Hagstrom screen.

Business Tenets

1. Is the business simple and understandable?

Knowledge helps to increase investment return and decrease risk. Buffett warns that if you buy a company for superficial reasons, then there is a tendency to dump the stock at the first sign of weakness. Investors need to be able to understand company factors such as cash flow, labor issues, pricing flexibility, capital needs, revenue growth and cost control.

2. Does the business have a consistent operating history?

Buffett avoids companies that are either solving difficult business problems or fundamentally changing their direction because previous plans were unsuccessful. Turnarounds rarely succeed in their turn. Buffett feels that the best returns come from companies that have been producing the same product or service for years.

While this tenet is primarily a qualitative element, the screen looks for positive operating profit over each of the last seven years as a basic test for consistent performance.

3. Does the business have favorable long-term prospects?

Buffett feels that the economic world is divided into a small group of “franchise” companies and a large group of commodity businesses. Companies with a franchise model produce a good or service that is needed or desired or has no close substitute, and they are companies that are not strongly regulated. Companies should have a strong, sustainable business advantage that protects sales and profits from competitors. Franchises have pricing flexibility to raise prices without the fear of losing market share or unit volume. Strong franchises have the strength to survive a major mistake.

It is important for the company to have a sustainable corporate advantage that acts as a barrier to make it difficult for others to compete. While this is a qualitative screen, many of the financial tenets— notably, measures of return on equity (ROE)—help to identify franchise companies.

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Management Tenets

4. Is management rational?

When considering a company, Buffett evaluates managers for their rationality, candor and independent thinking, among other characteristics.

Buffett looks for companies whose managers behave like business owners and act in a rational way, especially in the treatment of retained earnings and the investment of company profits. Hagstrom feels that the most important action of management is the allocation of a firm’s capital. Effective use and reinvestment of a company’s cash flow ultimately determines the growth of a firm and its long-term value. This issue becomes critical as a company matures and starts to generate excess cash flow that cannot be reinvested in the primary business line at a high rate of return.

A company with excess cash flow and below-average investment rates of return can ignore the problem, try to buy growth or return the cash to its shareholders. While Buffett has used these cash flows to acquire strong companies, he favors companies that use excess cash to repurchase shares. The share repurchases help to shore up the stock price through rising demand and increase the proportional claim toward income for the remaining shares. It is difficult to buy growth, as many companies pay too much for their acquisitions and run into difficulty integrating and managing the new business.

5. Is management candid with its shareholders?

Buffett holds in high regard managers who fully disclose company performance, equally reporting mistakes and successes. Buffett respects managers who report information beyond that required with generally accepted accounting principles (GAAP). Buffett looks for financial reports that enable the financially literate investor to determine the approximate value of a business, determine the likelihood that a firm can meet its financial obligations and gain an understanding of how well the managers are running the business.

6. Does management resist the institutional imperative?

Buffett looks for companies run by managers willing to think independently. Most managers follow the “institutional imperative” to imitate the behavior of other managers because they are afraid to stand out and look foolish. Hagstrom isolates three factors that strongly influence management’s behavior:

• Most managers cannot control their desire for activity, which leads to harmful decisions such as corporate takeovers.

• Managers tend to constantly compare the sales, earnings and compensation of their firm not only with true competitors, but also with companies well beyond their industry. These comparisons help to invite “corporate hyperactivity.”

• Most managers have an exaggerated sense of their own abilities.

Financial Tenets

7. Focus on return on equity, not earnings per share.

Buffett does not take quarterly or annual results too seriously when studying company financials. He finds it better to focus on three- to five-year averages to gain a feel for the financial strengths of a company.

While Wall Street typically measures company performance by studying earnings per share, Buffett looks for strong and consistent return on equity that is achieved without excess leverage or accounting gimmickry.

The AAII Buffett Hagstrom screen looks for return on equity above 15% over the last four quarters and for each of the last three fiscal years.

Companies can increase return on equity by increasing asset turnover, widening profit margins or increasing financial leverage. Buffett is not against the use of debt—financial leverage—but warns against excessive use of debt. Acceptable levels of debt vary from industry to industry, so a filter was added to the screen that requires debt-to-equity ratios to be below the respective industry norm.

8. Calculate “owner earnings.”

Buffett looks beyond earnings and even cash flow to measure company performance. Buffett judges performance using “owner earnings,” which Hagstrom defines as net income plus noncash charges of depreciation and amortization less capital expenditures (capex) and any additional working capital that might be needed. This is similar to the calculation of free cash flow, which also subtracts dividend payments.

9. Look for companies with consistent and high profit margins.

Buffett seeks franchise companies selling goods or services in which there is no effective competitor, either due to a patent or brand name or a similar intangible that makes the product unique. These companies typically have high profit margins because of their unique niche; however, simple screens for high margins may only highlight firms within industries with traditionally high margins. The AAII Buffett Hagstrom screen looks for companies with operating margins and net profit margins above their industry norms. Operating margin concerns itself with the costs directly associated with the production of goods and services, while net margin takes all of the company activities and actions into account. Follow-up examinations should include a detailed study of the firm’s position in the industry and how it might change over time.

10. For every dollar retained, make sure the company has created at least one dollar of market value.

The market recognizes companies that use retained earnings unproductively through weak price performance. Buffett feels that companies with good long-term prospects run by shareholder-oriented managers will gain market attention, which results in a higher market price. The AAII Buffett Hagstrom screen requires at least a dollar-for-dollar share price increase for each dollar added to retained earnings over the last five years.

Valuing a Stock

11. What is the value of the business?

Even if you have identified a good company, it does not necessarily represent a good investment unless it can be purchased at a reasonable price.

12. Purchase stock if it can be acquired at a significant discount to its valuation.

Many investors turn to simple multiples, such as the price-earnings (P/E) ratio, to help establish a preliminary hurdle before an in-depth analysis is performed. Since Buffett likes to focus on free cash flow, the price-to-free-cash-flow (P/FCF) ratio is used in the screen.

The lower the price-to-free-cash-flow ratio, the better. However, a company with higher growth deserves to trade at a higher multiple than a slower-growing firm. To adjust for varying growth rates, the price-to-free-cash-flow ratio was divided by the free-cash-flow growth rate to help equate value to growth. The 30 companies with the lowest ratio of price to free cash flow to free-cash-flow growth are presented in the final screening results.

Summing It Up

Buffett’s approach identifies “excellent” businesses based on the prospects for the industry and the ability of management to exploit opportunities for the ultimate benefit of shareholders. He then waits for the share price to reach a level that would provide him with a desired long-term rate of return.

Most investors have little trouble understanding Buffett’s philosophy. The approach encompasses many widely held investing principles. Its successful implementation is dependent on the dedication of the investor to learning and following the principles. It requires the ability to stick to the approach during times of market volatility. But for individual investors willing to do the considerable homework involved, the Buffett approach offers a proven path to investment value.

Stocks Passing the Buffett Hagstrom Screen

(Ranked by the Ratio of Price to Free Cash Flow to Free-Cash-Flow Growth)

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Keep in mind that no matter how well a stock screening methodology has performed (or how badly it has underperformed) over the long term, stock screening is only the first step in the stock selection process. You will want to do your homework to see why these companies are at their current levels. Only then will you gain insight into those that will continue to languish and those that may eventually flourish.

The stocks meeting the criteria of the approach do not represent a “recommended” or “buy” list. It is important to perform due diligence to verify the financial strength of the passing companies and to identify those stocks that match your investing tolerances and constraints before committing your investment dollars. Keep in mind that the quantitative screens AAII has developed are based upon our interpretations of published works tied to the market gurus.