Berkshire Hathaway (BRK.A 0.64%) (BRK.B 0.54%) has a massive stock portfolio with dozen of companies worth well over $300 billion, and many of its positions were selected by CEO Warren Buffett himself.

For the most part, Buffett and his investment managers are known for buying the stocks of tried-and-true businesses that are well established and stable but still have long-term growth potential. But that's not always the case, and not every "Buffett stock" is worth buying now. Here are two in particular that look like attractive long-term investments after the recent market decline and one growth stock in Berkshire's portfolio that you might want to think twice about.

1. This Buffett bank stock could be a big winner in the rising-rate environment

Bank of America (BAC 1.53%) is the second-largest stock position in Berkshire's portfolio. As of the latest information, Berkshire owned just over a billion shares of the megabank, which translates to an ownership stake of about 13%.

The bank stock is down by about 35% from its recent high, mainly due to recession fears. In recessions, banks often see an uptick in loan defaults as well as a slowdown in consumer demand for borrowing. However, Bank of America is also well positioned to benefit from the current environment. As the Federal Reserve raises rates, it is likely to result in billions in additional net interest income for Bank of America. The bank has a massive base of low-cost and non-interest-bearing deposits, and rate hikes have a big impact on the bottom line.

We've already started to see this in the bank's second-quarter results, and management estimates that a 100-basis-point (one percentage point) shift in the yield curve would produce an additional $5 billion in net interest income annually, which could certainly help offset any negative impact of an economic slowdown.

2. A mini-Berkshire that has one big advantage over Buffett

Markel (MKL 0.53%) is often referred to as "baby Berkshire," and it's easy to see why. An insurance company at heart, Markel also invests its float in a portfolio of stocks, as well as in private businesses, through its Markel Ventures division. So it wasn't too surprising to see Berkshire add Markel to its stock portfolio this year.

It's important to note that Markel not only has a similar business model to Berkshire Hathaway, but it actually has one key advantage over it -- its size. With a market cap of about $16 billion, Markel is less than 3% of Berkshire's size. This means that Markel can produce needle-moving returns from smaller investments (like its venture capital business) than Berkshire can. As a simplified example, if Berkshire invests $100 million in a stock that ends up producing 100x returns, it would only result in about a 2% increase in the company's market value. For Markel, such an investment would be game-changing.

In short, Markel uses a time-tested business model and is comparable to an earlier-stage investment in Berkshire Hathaway itself.

3. A high-potential fintech that faces some big headwinds

A few years ago, Berkshire did something that it rarely does and invested in a high-growth business that had just made its public debut. While the investment wasn't made by Buffett himself, Berkshire added shares of Brazil-based fintech StoneCo (STNE 0.07%).

For a while, StoneCo was one of the best performers in Berkshire's portfolio, but the stock has been absolutely hammered in the recent downturn, with shares down by more than 90% from the highs. And while the business still has lots of potential, it's also become much riskier. The company reported a hefty net loss in the second quarter, compared with a profit a year ago, and growth has slowed down tremendously. Inflation is higher in StoneCo's market than it is in the United States, and a recession could cause a sharp decline in consumer spending. Plus, StoneCo's CFO recently decided to leave the company.

To be sure, StoneCo could end up being a home run for patient investors. If recession fears subside, growth could rebound. The company is slowly rolling out its credit card business, which could be a massive revenue driver long term. But there's too much that can go wrong in the near term, so I'm staying on the sidelines.