It has been a fairly solid year for the markets in 2024 as the S&P 500 has risen by around 18% thus far. However, it's not hard to find stocks that have done even better. A good place to look is in Warren Buffett's Berkshire Hathaway portfolio, which invests in many of the world's top stocks. You'll find many quality, safe stocks to own for the long term. And some of them have been solidly outperforming the market.

Amazon (NASDAQ: AMZN), T-Mobile US (NASDAQ: TMUS), and American Express (NYSE: AXP) are among the brightest investments in Berkshire's portfolio this year. These are the types of investments you can hang on to for not only years but decades. Here's how they've been doing thus far and why they can still soar higher.

Amazon

This e-commerce and tech giant is not a big holding in the Berkshire Hathaway portfolio, accounting for just 0.6% of the portfolio's overall weight. But it has been one of the better-performing stocks there, with its value rising by 21% since the start of the year.

The stock has benefited from the hype in artificial intelligence (AI) as the company has invested in chatbot-maker Anthropic and it plans to invest a whopping $100 billion over the next decade to focus on its data center infrastructure. Data centers are going to be growing in importance in the future as more companies go to the cloud and develop AI models.

On the e-commerce side of things, Amazon is also launching a new discount service to better compete with cheap online retailers such as Shein and Temu (which PDD Holdings owns). That can potentially boost its growth rate, which was at 10% in the company's most recent quarter as sales topped $148 billion for the period ending June 30.

Despite all these positive investments and potential catalysts, Amazon's stock still trades at a fairly modest 44 times earnings, which is a bit unusual for a stock for which investors normally pay a much higher premium. It may only be a matter of time before the stock rallies even more.

T-Mobile US

Up 28% this year, T-Mobile is another stock which has been doing well of late. The telecom company has been posting some strong numbers this year. In its most recent quarter, T-Mobile reported its highest postpaid phone net customer additions in its history at 777,000 and it hit a milestone of 100 million postpaid customers in total.

There should be even more growth on the horizon for the company as it plans to acquire the majority of U.S. Cellular for $4.4 billion, which will expand its coverage in rural areas. T-Mobile acquired Sprint in 2020 for the much more massive price tag of $26 billion. T-Mobile's consistent pursuit of growth and success in winning over customers makes it one of the better telecom stocks to own in the long run.