Berkshire Hathaway (BRK.A -0.39%) (BRK.B -0.56%) CEO Warren Buffett is a lodestar for many investors, and for good reason. His stock-picking acumen has yielded astounding returns on capital for Berkshire shareholders over the years.

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Which Warren Buffett stocks are worth buying in May? Although the Oracle of Omaha has become decidedly more cautious when it comes to U.S. stocks in recent times, Berkshire's portfolio still contains a handful of outstanding buys for patient investors. Here are two holdings that ought to deliver above-market returns for those with a long-term mindset. 

1. Apple

Apple (AAPL -1.32%) has built a thriving business with a wide economic moat thanks to its user-friendly Mac and iPhone. These intuitive interfaces seamlessly integrate a diverse array of apps, drastically cut down on conflicts between apps, and most importantly are the basis for the company's reputation for products that "just work" right out of the box.

The sleek design of the iPhone, which raked in an eye-popping $51.3 billion in sales in the most recent quarter, is also a crucial component in its wide competitive moat. Namely, the tech giant's flagship product has become a cultural icon. An iPhone has become a sign of personal financial success in many countries, as well as a must-have fashion accessory.

As a direct result, Apple has been able to rapidly capture market share in key emerging nations like India in recent quarters, despite fierce competition from lower priced alternatives. 

Apple's well-earned reputation for making easy-to-use products that are both reliable and stylish is the core reasons Buffett views the company as one of the best businesses in Berkshire's diverse portfolio. What it all boils down to is this: The company's core enormous earnings power ought to remain intact for the foreseeable future due to its lack of viable competition and beloved status among users.

So, even though Apple's stock does have a moderately low earnings yield of 3.77%, its proven ability to fend off competition is arguably worth the price of admission.  

2. Johnson & Johnson

Johnson & Johnson (JNJ -0.36%) has been among Berkshire's few long-term holdings in healthcare for a couple of solid reasons. Despite the inherent disadvantage of operating in arenas like pharmaceuticals and medtech that are heavily dependent on time-limited patents to protect profits, J&J has been able to build a formidable economic moat, a AAA-rated balance sheet, a 61-year history of annual dividend increases, and a well-earned reputation for savvy capital allocation.

As a recent example, J&J acquired Abiomed late last year in a move that significantly bolstered its cardiovascular medtech portfolio ahead of the spinoff of Kenvue. This latest medtech acquisition opens up another high-growth opportunity for the company in the years ahead.

What's important to understand is that most mergers and acquisitions in healthcare actually turn out to be value sinks due to the high premiums involved, innate regulatory risks, and the ever-present threat of new competitors coming to market. J&J, by contrast, has repeatedly been able to avoid these pitfalls by hitting on winning companies like Abiomed that ultimately enhance its overall value proposition to shareholders. 

J&J's successful capital allocation strategy, heavy investment on internal pipeline development, and rich tradition of dividend increases have made its stock a tremendous investment for long-term stakeholders:

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As such, this Buffett stock is arguably worth buying in any type of market.