Perhaps no stock portfolio is more closely followed than that of Warren Buffett-led Berkshire Hathaway (NYSE:BRK-A) (NYSE:BRK-B). While I feel like most "Buffett stocks" are great long-term investments to make at any time -- after all, that's why Buffett chose them -- there are some that stand out as particularly attractive opportunities.

With that in mind, here's why one of Buffett's favorite bank stocks and the stock that makes up most of Buffett's net worth could both be fantastic investments in the coming years.

Warren Buffett

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All-around great numbers, with a high-potential future growth driver

Investment bank Goldman Sachs (NYSE:GS) has been an underperformer in a generally strong financial sector, but it may not last too much longer if Goldman's impressive results continue.

One of the biggest issues holding the company back has been dismal trading revenue, mainly as a result of low volatility, both in terms of the stock market and interest rates. However, that has changed in 2018. Thanks to the volatile first quarter, Goldman's fixed income, currency, and commodity (FICC) trading revenue, the biggest weak spot in recent years, soared by 23% year over year. Stock market volatility helped push equity trading revenue up by an even more impressive 38%.

In addition, Goldman's other business segments have been quite strong. Investment management revenue is up 18%, underwriting revenue soared 27%, and the bank just got a big boost from tax reform.

The area of Goldman's business I'm most excited about, however, is its push into consumer banking with its Marcus platform. Its consumer-friendly and easy-to-use lending platform just reached $3 billion in originated loans, a remarkable amount considering that the platform launched in late 2016 and surpassed $1 billion less than a year ago. And with more financial flexibility than other online banks, Goldman offers better terms on deposits, which so far has been successful. In fact, as of this writing, Marcus offers the best rates on both CDs and savings accounts of any major online lender.

The U.S. unsecured debt market is about $1 trillion in size, and while the Marcus platform's growth has been impressive, there's still tremendous potential here.

The Buffett stock

No stock is more of a "Warren Buffett stock" than Berkshire Hathaway itself, and I believe the company is worthy of a closer look in May.

First off, Berkshire is a great stock to buy at any time. With a portfolio of more than 60 high-quality subsidiary companies and a massive stock portfolio, Berkshire is effectively a diversified investment portfolio managed by the greatest investor of all time and his trusted associates.

One particularly smart reason to consider Berkshire Hathaway now is for its massive cash hoard, which stood at $116 billion at the end of 2017. Warren Buffett has said that he prefers to keep at least $20 billion in reserves at all times, but this still leaves nearly $100 billion of capital that Buffett and company can't wait to put to work, which is currently earning next to nothing.

The point is that more than one-fifth of Berkshire's entire market cap is sitting in cash on the company's balance sheet. If market volatility or rising rates in 2018 or 2019 finally gives Buffett a reasonable way to put this money to work, it could have a huge positive impact on Berkshire's earning power. As my colleague Jordan Wathen wrote, if Berkshire acquired $100 billion of businesses at an average price of 20 times earnings, it would translate to $5 billion in additional annual earnings -- a 34% increase over 2017's full-year profit.

In a nutshell, it could be a smart idea to buy now before the company figures out how to deal with its cash problem.

Matthew Frankel owns shares of Berkshire Hathaway (B shares). The Motley Fool owns shares of and recommends Berkshire Hathaway (B shares). The Motley Fool has a disclosure policy.