Warren Buffett has helped steer Berkshire Hathaway to gains of more than 2 million percent over the last 54 years, good for an average annual growth rate of roughly 20% across the stretch -- a staggering return that roughly doubled the market's annual gains.

That kind of performance makes it easy to be a fan of Buffett. And it also suggests that it's worth monitoring Berkshire's stock holdings with an eye out for when worthwhile investing opportunities might arise. This month, Apple (NASDAQ:AAPL), Bank of America (NYSE:BAC), and Costco (NASDAQ:COST) look like smart buys.

Warren Buffett.

 Warren Buffett. Image source: The Motley Fool.

Apple

Despite having a known aversion to the technology sector, Buffett started buying Apple in 2016 and continued with a push that made it Berkshire's biggest equity holding by far. There have since been a few bumps in the road.

According to a tally by my Motley Fool colleague Matthew Frankel, Berkshire's overall Apple investment traded down roughly $21 billion early in January. The stock has subsequently seen some recovery, and Buffett's famous long-term approach to investing means he probably wasn't losing much sleep over the volatility. But retail investors still have a chance to build a position in Apple at prices that beat the average paid by the Oracle of Omaha and his investing firm.

Apple stock took a beating as the broader market endured sell-offs at the end of 2018 and sales for the company's iPhone came in significantly below initial expectations -- largely due to a steep sales drop in the Chinese market. 

Buffett has remarked on the strength of Apple's hardware brand as a worthwhile reason to own the stock, but much of his bullish thesis has always revolved around the impressive software ecosystem that the company has built -- and the potential to leverage this advantage with new services. There's still substantial momentum and room for growth in software and services. And there are avenues to long-term growth in hardware as Apple implements more substantial feature upgrades with future iPhones and pushes into categories like wearables and smart-home and other Internet of Things devices.

There's also the company's rising dividend profile to like. Berkshire itself has opted not to pay a dividend and instead uses its massive cash pile to target acquisitions and investments across a variety of industries and fields. But Buffett is famously a fan of stocks that return cash to shareholders. Apple has been ramping up its dividend in recent years, and has roughly doubled its payout since 2012. And it looks like the company will continue to cut checks to shareholders as it moves through its transition to become a more software-focused business.

Despite some recent stumbles for the iPhone, Apple stock is worthwhile trading at roughly 15 times this year's expected earnings.

Check out the latest earnings call transcripts for Apple, Bank of America, and Costco.

Bank of America

Buffett is big on bank stocks -- with half of Berkshire's 10 biggest holdings by weight having a substantial banking component. Bank of America is Berkshire's top holding in the space and its second-biggest holding overall.

It's also America's second-largest bank in terms of assets, and it's been using its scale advantages and carrying out internal initiatives to reduce expenses and improve margins. The company has also made substantial progress in bolstering its online services. These steps have helped the company steadily lower its efficiency ratio -- a measure of the bank's operating expenses against its net revenue -- and get back to regular profitability. 

Buffett poured into Bank of America stock in the wake of the financial crisis, catching shares at a relative low point and seeing strong returns in subsequent years. Some stigmas from the financial crisis still surround the company, and perhaps not entirely without reason -- as write-offs, fines, and legal expenses stemming from the crash may have cost it roughly $190 billion. But the company appears to have done a commendable job rebuilding and restructuring to reduce its risk amid volatility and to better serve its customers. 

The company is back to delivering a 10% return on equity and 1% return on assets, and it expects to repeat last year's 58% efficiency ratio in 2019 and 2020. Bank of America stock yields roughly 2%, and the company has a five-year streak of payout growth. Even after big gains in recent years, the company's shares still sport a decent yield and don't look prohibitively priced trading at roughly 11 times trailing earnings and 10 times this year's estimates. 

Costco

Stocks in the brick-and-mortar retail sector have generally been a bit of a shaky prospect amid the ongoing rise of e-commerce, but that doesn't mean there haven't been standouts. The companies that have managed to thrive despite the online retail pressure could have advantages that let them continue to deliver strong performance. And Costco certainly looks to be on the right track.

Its bulk-centric membership service has been -- and will likely continue to be -- immune to e-commerce pressures because it allows the company to offer value propositions that are difficult to beat even for online outlets. There's still considerable growth opportunity as it expands its in-house brand offerings in appliances, furniture, and other categories. 

Costco's dividend deserves some attention as well. While the yield of 1.1% might not look like much, its returned-income profile is more attractive than a first glance might suggest. The company boasts a 15-year history of annual payout growth and has raised its annual payout roughly 60% over the last five years -- and that's not counting the substantial special dividends that it paid in 2013, 2015, and 2017.

COST Dividend Chart

COST Dividend data by YCharts.

With the company's dividend payout ratio sitting at roughly a third of trailing earnings and a third of free cash flow, the warehouse retail giant still has plenty of room to continue growing its annual payout even if the next special dividend is a way off.

That's especially true because its outlook in cash generation is bright. This is a business with a defensible operating moat, a fast-growing dividend, and a strong brand, and it has the makings of a sturdy, long-term performer.