A $1,000 investment in Berkshire Hathaway stock in 1965 -- the year Warren Buffett took control of the once-struggling New England textile mill -- would have been worth $15.3 million at the end of 2016. Suffice to say, it's worth your time to check out what stocks Berkshire Hathaway owns.

Two of them worth considering right now are Apple (AAPL 0.52%) and Restaurant Brands International (QSR -0.75%).

Apple store interior flooded with customers during iPhone X launch.

Apple had a strong holiday quarter thanks to high demand for iPhone X. Image source: Apple.

Apple is one of Berkshire's top bets

Berkshire Hathaway owned 134,092,782 shares of Apple as of the most recent 13-F filing for the quarter ending in September 2017. Those shares are worth about $23 billion at the stock's current price. Berkshire Hathaway first revealed a stake in Apple in 2016.

In February 2017, Buffett summed up the case for investing in Apple, saying:

Apple strikes me as having quite a sticky product and enormously useful product that people would use ... The continuity of the product is huge, and the degree to which their lives center around it is huge. And it's a pretty nice ... franchise to have with a consumer product.

Apple's lead in retail sales per square foot is a telling sign of its brand strength. Apple leads all retailers with a whopping $5,546 of sales per square foot, according to research from CoStar. This ranks ahead of top jewelry brand Tiffany and also bucks the trend of declining sales per square foot for the retail industry over the last decade.

Apple's success with its line of iPhones, iPads, and Macs is carrying over to growth in services revenue, which includes AppleCare protection plans, Apple Pay, Apple Music, and App Store and iTunes content. Services revenue grew 23% to $29.98 billion in fiscal 2017, about 13% of the total.   

Services generate much higher margins than sales of hardware, such as iPhones, and also provide Apple a fast-growing, predictable revenue stream. Services represents only 13% of Apple's total revenue, but management expects to double this source of revenue by 2020.

Apple stock currently trades for 15 times fiscal 2018 earnings estimates, a discount to the S&P 500 Index P/E of 19.8 earnings. For those looking for income, Apple also sports a dividend yield of 1.4%, and a payout ratio of just 26%. Apple's cash-rich balance sheet and ability to pump out huge profits gives it a lot of wiggle room to increase that payout in the future.

With services taking off, and demand for the new iPhone X expected to be strong, this could be a good time to think about joining the Oracle and adding shares of Apple to your nest egg.

Corporate logos of Burger King, Tim Hortons, and Popeyes Louisiana Kitchen underneath logo of Restaurant Brands International.

IMAGE SOURCE: RESTAURANT BRANDS INTERNATIONAL.

A family of restaurant brands run by savvy investors

A small, unrecognized, but appetizing investment listed in Berkshire Hathaway's most recent 13-F filing is Restaurant Brands International (RBI), the owner of fast-food chains Burger King, Tim Hortons, and Popeyes Louisiana Kitchen. Berkshire owned 8,438,225 shares at last report, worth $515 million at the time of this writing.

To understand why Buffett likes RBI, we have to consider RBI's largest shareholder, 3G Capital, a Brazilian investment firm that Buffett has partnered with on previous deals (most notably the Kraft Heinz merger).

In Berkshire Hathaway's 2015 shareholder letter, arren Buffett had high praise for 3G Capital co-founder Jorge Paulo Lemann and his partners:

Jorge Paulo and his associates could not be better partners. We share with them a passion to buy, build and hold large businesses that satisfy basic needs and desires.

3G has made a name for itself by taking large stakes in well-known consumer goods companies and then improving their performance to position them for long-term growth. Its operating methods involve removing excess costs, improving margins, and using innovation and marketing to grow revenue.

RBI believes the market opportunity internationally for its restaurant chains is several times the company's existing footprint. For example, while competitor Kentucky Fried Chicken has over 5,200 restaurants open in China, RBI's Popeyes Louisiana Kitchen only has 2,809 open worldwide.

RBI's stock has only been trading for a few years, but investors clearly see the growth potential given the stock's relatively high P/E ratio of 31 times 2017 earnings estimates. RBI has grown adjusted earnings per share 59% cumulatively since 2015, and analysts forecast the company to grow earnings 19% annually over the next five years.

RBI's growth potential coupled with the support of two very influential investors makes RBI a stock worth considering for the long term.