Even after stepping down as chief executive of Berkshire Hathaway late last year, Warren Buffett's wealth remains deeply tied to the conglomerate and its equity holdings. Among the company's top three positions 鈥?Apple, American Express, and Alphabet 鈥?these alone account for more than half of the entire stock portfolio. Each represents a high-quality business with wide economic moats and the capacity for sustained compound growth. But if forced to pick just one, which stands out as the optimal choice today? Let's break it down.

Apple: The Ecosystem Powerhouse

Apple is Berkshire's largest holding, representing roughly 22% of the portfolio. Buffett has long favored this stock for its world-class compounding business model. The company's core strength lies in the iPhone and its hardware lineup. Smartphones and computers follow highly predictable upgrade cycles, delivering a nearly perpetual stream of stable revenue. Yet the true competitive barrier sits in its closed-loop ecosystem: it locks in users and monetizes them through high-margin services revenue. Income streams are highly diversified, including search revenue-sharing agreements with Google, App Store commissions, Apple Pay transaction fees, and subscription services like iCloud storage. With a rock-solid business model, the recently launched foldable iPhone Duo could serve as a fresh growth catalyst. Foldables aren't new, but Apple's refined integration of software and hardware is likely to reignite the category and attract a wave of new users.

American Express: The Premium Payments Franchise

American Express makes up more than 17% of Berkshire's position and serves as another classic example of a compounder. The charge card provider has become a status symbol among affluent customers: it charges premium annual fees in exchange for exclusive perks and benefits. Meanwhile, cardholders spend on average three times more than typical consumers, allowing the company to command higher merchant transaction fees. Like Apple, American Express tightly controls its own ecosystem. It operates a closed-loop payment network, acting as both issuer and clearinghouse, profiting from both ends of every transaction while accumulating vast amounts of spending data. The majority of its cards target high-net-worth individuals, and most are charge cards requiring full monthly repayment, which significantly reduces credit risk. As membership grows and per-person spending steadily rises, American Express can sustain long-term earnings growth.

Alphabet: The AI-Fueled Growth Contender

Alphabet ranks as Berkshire's third-largest holding, with a stake close to 13%. It was one of Buffett's final major moves before his "semi-retirement," and under his guidance, successor Greg Abel has continued adding to the position. Alphabet's biggest advantage is its full-stack AI capabilities, firm control over traffic distribution channels, and highly monetizable advertising business. Its in-house AI chips provide a significant cost edge in cloud computing; the investment in AI infrastructure pays for itself within a year of deployment. The company has also partnered with Broadcom to sell these custom chips to external clients like Anthropic, a segment expanding rapidly. Its proprietary large language models have dramatically cut both training and inference costs. AI capabilities are being deployed across all operations, and Google Search is a prime example: new tools powered by the Gemini model, such as AI overviews and AI search modes, are driving growth. Beyond that, Alphabet controls two major traffic gateways 鈥?the Chrome browser and the Android operating system 鈥?and holds a deal with Apple to remain the default search engine on its devices, giving it an unmatched distribution advantage.

The Verdict: One Clear Winner

All three businesses boast solid fundamentals and are worthy of long-term holding. But if it comes down to a single pick, Alphabet takes the top spot. Its forward price-to-earnings ratio sits at under 17 times, the lowest of the trio, while its long-term growth prospects are the most compelling.