Warren Buffett is an American investor, business tycoon, and philanthropist. Known as the “Oracle of Omaha,” Buffett is best known for his strict adherence to value investing and frugality despite his immense wealth. Warren Buffet owns an investment firm, Berkshire Hathaway, which owns 5.92% of Apple, valued at nearly $170 billion.
Warren Buffett: An American investor, business magnate, and philanthropist known as the “Oracle of Omaha.”
Value Investing: Buffett is renowned for his value investing philosophy, which involves identifying undervalued stocks and holding them for the long term.
Frugality: Despite his vast wealth, Buffett is known for his frugal lifestyle and modest spending habits.
Berkshire Hathaway: Buffett is the chairman and CEO of Berkshire Hathaway, a multinational conglomerate holding company based in Omaha, Nebraska.
Apple Investment: Berkshire Hathaway owns a significant stake in Apple, amounting to 5.73% of the company. This stake is valued at over $130 billion.
Apple returned $106B to shareholders in fiscal 2025, close to its $112B net income. Source: AppleForm 10-K filings via SEC EDGAR XBRL company facts. Analysis by The Business Engineer.
How we source: figures on this page come from the company’s own filings (SEC 10-K, 10-Q and earnings releases, or its annual report), with the period stated next to each number. Last refreshed October 2026. Our methodology.
Value investing is a strategy advocating the purchase of stocks that are underappreciated by other investors or the broader market. Value investing was popularised by investor Warren Buffett, but the approach was pioneered by Benjamin Graham and David Dodd at Columbia Business School in the early 1920s. Graham would later go on to release the seminal book The Intelligent Investor in 1949.
The Buffet Indicator is a measure of the total value of all publicly-traded stocks in a country divided by that countryโs GDP. It’s a measure and ratio to evaluate whether a market is undervalued or overvalued. It’s one of Warren Buffet’s favorite measures as a warning that financial markets might be overvalued and riskier.
The circle of competence describes a personโs natural competence in an area that matches their skills and abilities. Beyond this imaginary circle are skills and abilities that a person is naturally less competent at. The concept was popularised by Warren Buffett, who argued that investors should only invest in companies they know and understand. However, the circle of competence applies to any topic and indeed any individual.
Economic or market moats represent long-term business defensibility. Or how long a business can retain its competitive advantage in the marketplace over the years. Warren Buffet who popularized the term โmoatโ referred to it as a share of mind, opposite to market share, as such it is the characteristic that all valuable brands have.
The Golden Circle attempts to explain how certain businesses can inspire others and differentiate themselves in the market. Originally developed by author Simon Sinek, the concept helps businesses identify their purpose and then communicate that purpose to consumers in a meaningful way so that the brand can be highly differentiated in the marketplace.
The 5 Whys method is an interrogative problem-solving technique that seeks to understand cause-and-effect relationships. At its core, the technique is used to identify the root cause of a problem by asking the question of why five times. This might unlock new ways to think about a problem and therefore devise a creative solution to solve it.
First-principles thinking โ sometimes called reasoning from first principles โ is used to reverse-engineer complex problems and encourage creativity. It involves breaking down problems into basic elements and reassembling them from the ground up. Elon Musk is among the strongest proponents of this way of thinking.
Second-order thinking is a means of assessing the implications of our decisions by considering future consequences. Second-order thinking is a mental model that considers all future possibilities. It encourages individuals to think outside of the box so that they can prepare for every and any eventuality. It also discourages the tendency for individuals to default to the most obvious choice.
Apple in charts
Services earned a 76% gross margin in the June 2026 quarter; hardware earned 40%. Source: Applequarterly earnings releases (Form 8-K, SEC EDGAR). Gross margin = net sales minus cost of sales, calculated. Analysis by The Business Engineer.Apple at a glance: $109B of revenue and $35.7B of operating income in one quarter. Source: Applequarterly earnings releases (Form 8-K, SEC EDGAR) (fiscal Q3 2026). YoY calculated. Analysis by The Business Engineer.
Gennaro Cuofano is a CRO and tech executive who has worked in AI since late 2015, starting with bringing NLP, natural-language generation, voice and chatbot products to the marketing industry. His background is in law and finance: he holds a Master's degree in Law and an International MBA with an emphasis on corporate finance (LUISS Business School and the University of San Diego, 2012), and worked as a financial analyst at a real-estate investment firm in San Diego and as an assistant controller. His work focuses on business model strategy, business engineering and, more broadly, structural analysis: how companies make money, read from their own filings. He created FourWeekMBA and leads research there and at The Business Engineer, his newsletter on AI and business strategy, with over 95,000 subscribers and more than 1,000 published analyses. His writing has also appeared on Entrepreneur (for example, How to Digitize a Family Business in Europe) and HackerNoon. Find him on LinkedIn and Substack. See how we source.
Scroll to Top
Discover more from FourWeekMBA
Subscribe now to keep reading and get access to the full archive.
