The dog days of summer have arrived, and they've brought with them a stock-market swoon. After soaring 20% from the beginning of the year through the end of July, the S&P 500 index has dipped 4% in August.

However, this presents an opportunity for long-term investors to buy on the dip. With that in mind, let's see what stocks have captured the attention of three Motley Fool contributors.

Rising line on a stock market chart with a golden dollar sign.

Image source: Getty Images.

Excellent management like Microsoft's is hard to find

Jake Lerch (Microsoft): With Microsoft (MSFT 0.55%) down 11% from its recently notched 52-week high, the market is giving investors an opportunity to buy at a discount. Considering I've written that Microsoft will top the list of America's largest companies by 2030, it should come as no surprise that I remain bullish on the company.

Microsoft's diverse business segments and iconic software products are its star assets. Still, I want to discuss a different asset that I feel is often underappreciated: its fantastic management.

Next February, Satya Nadella will celebrate his 10th anniversary as Microsoft's chief executive officer (CEO). During his time at the helm, shares of Microsoft have increased in value by a mind-boggling 779%. That means $10,000 invested at the start of Nadella's tenure as CEO would have grown to nearly $88,000 today.

Compare that with the 10 years before Nadella's arrival to see his impact. Shares of Microsoft grew only 35% between 2004 and 2014, as the company struggled to find its way under the leadership of former CEO Steve Ballmer.

It's important to remember that companies -- as large and complex as they might be -- are still run by living, breathing CEOs. And, unsurprisingly, some are better at the job than others.

Recently, a court filing revealed that Nadella set an internal goal for Microsoft to hit $500 billion in sales by 2030. It's undoubtedly an ambitious goal, but given his track record of success, it's achievable.

And it's yet another reason long-term investors should consider buying Microsoft on the dip.

A Nu way of thinking could enrich shareholders and depositors alike

Will Healy (Nu Holdings): One stock that has avoided the market dip is Nu Holdings (NU -0.83%). Nu Holdings operates Nubank, one of the world's largest platforms for digital financial services.

While that's a notable accomplishment, the Brazil-based bank stands out for a different reason. Between July 2021 and July 2022, over 5.7 million Brazilians received their first credit card through Nubank. This is significant because a large percentage of Latin Americans are unbanked, meaning they lack access to bank accounts and credit cards and are not part of the mainstream financial system.

Hence, it's no surprise that its customer base of 85 million grew by over 18 million over the last year. As a result, 49% of adult Brazilians, about 80 million people, hold a Nubank account.

Nonetheless, that level of market saturation likely means growth in Brazil will plateau soon. To address that issue, the company recently expanded into Mexico and Colombia, where customer counts grew 33% and 133%, respectively. Such growth levels indicate that it could repeat its success in those countries.

Indeed, its rapid expansion continues: Its yearly growth rate in the first half of 2023 was 71%, taking revenue to almost $3.5 billion. Nu Holdings also kept expense growth significantly below that of revenue, helping its net income for the period rise to $367 million, up from a loss of $75 million in the first two quarters of 2022.

Nu Holdings received an investment before its initial public offering (IPO) from Warren Buffett's Berkshire Hathaway (BRK.A -1.29%) (BRK.B -1.41%). Then it launched its IPO in late 2021, near the height of the 2021 bull market, so the stock's value dropped considerably in 2022.

However, Nu stock has nearly doubled since the beginning of the year, and a forward price-to-earnings (P/E) ratio of 45 arguably makes it a relative bargain, considering its rapid growth rate. Assuming Nubank's popularity continues to grow in Mexico and Colombia, the fintech stock should move higher as the company continues to bring more people into the mainstream financial system.

Datadog's strong earnings growth will make the stock cheaper in a hurry

Justin Pope (Datadog): Datadog's (DDOG -4.42%) stock crashed after the company failed to meet the market's high expectations for its second-quarter earnings. But here's the thing: A short-term stumble can be an opportunity for those able to zoom out and think in years, not months.

Datadog is a cloud observability service. Its software monitors all aspects of a company's technology stack, including software and hardware, to track performance, perform analytics, and identify and solve performance problems. In other words, it's a watchdog making sure your technology works properly.

The company has more than tripled revenue over the past two years, converting 22% of revenue to free cash flow. Datadog's business has more than 26,000 customers and a net revenue retention rate (NRR) above 120%, meaning customers spend more on the product over time.

DDOG Revenue (TTM) Chart

DDOG Revenue (TTM) data by YCharts.

There are millions of companies worldwide, and observability is a mission-critical service in an increasingly tech-driven business environment. It seems reasonable that Datadog could continue double-digit revenue growth for the foreseeable future. The company is already profitable, so ongoing growth should trickle down to earnings. Analysts believe earnings per share (EPS) could grow by an average of 25% annually over the next three to five years.

The stock trades at a hefty forward P/E of 69, but given its bright growth outlook, long-term investors could consider making modest purchases of shares on further declines. Datadog is a quality, high-growth company with a long runway ahead. Such stocks often grow into their valuation over time, and then some.