Stock prices have fallen sharply on recession fears this year, causing the Nasdaq Composite to slip deep into a bear market. In fact, the tech-heavy index has fallen nearly 36% from its November peak, marking its largest decline in the last decade.

Many individual stocks are in the same boat. Nvidia (NVDA 1.20%) and Microsoft (MSFT 0.47%) have seen their share prices fall 66% and 33%, respectively. Neither stock has suffered a worse loss at any point in the past 10 years. But both companies are still backed by a solid investment thesis, making this a once-in-a-decade buying opportunity.

Here's what investors should know.

Nvidia: A leader in graphics and accelerated computing

Nvidia is shaping the future of countless industries. Its graphics processing units (GPUs) bring revolutionary visual effects to video games and films and lend unparalleled processing power to complex data center workloads like analytics and artificial intelligence (AI). In fact, Nvidia currently holds more than 90% market share in workstation graphics and supercomputer accelerators, and Forrester Research recently said Nvidia GPUs are synonymous with AI infrastructure.

In recent years, the company has doubled down on its data center businesses, reinforcing its leadership in graphics and accelerated computing. For instance, Nvidia added high-performance networking solutions to its portfolio with its acquisition of Mellanox in 2020, and the company subsequently debuted a new kind of processor: the data processing unit (DPU). Nvidia DPUs accelerate data center workloads by offloading networking, storage, and security tasks from central processing units (CPUs).

Nvidia has also expanded into software. Its AI Enterprise suite helps businesses build AI-powered applications in end markets like healthcare, manufacturing, and retail. Similarly, its Omniverse platform allows creators to collaborate on 3D-design projects, enables developers to build intelligent digital humans, and empowers researchers to train AI models for self-driving cars and other autonomous machines.

Many investors are well aware that Nvidia delivered abysmal financial results in the most recent quarter due to a big drop in gaming revenue as high inflation stifled consumer demand. But the company has still delivered decent results over the past year. Revenue jumped 36% to $29.7 billion, and generally accepted accounting principles (GAAP) earnings increased 9% to $3.05 per diluted share. Moreover, the long-term investment thesis is still intact despite short-term headwinds.

Nvidia is still the gold standard in graphics and accelerated computing, and the company should benefit greatly as technologies like AI and virtual reality (including the metaverse) continue to evolve. In fact, management puts its addressable market at $1 trillion, and with shares trading at a reasonable 9.6 times sales, investors shouldn't pass on this once-in-a-decade buying opportunity.

Microsoft: Mission-critical software and infrastructure

Microsoft is the foundation on which countless businesses are built. Its cornerstone platform, Microsoft 365, is the most popular enterprise application suite of any kind. It brings together a broad array of mission-critical and market-leading products, including Office 365 for productivity; Teams for communication; Power BI for business analytics; and Defender, Sentinel, and Azure Active Directory for cybersecurity.

Microsoft is also gaining momentum in cloud computing. As of the second quarter, Microsoft Azure held a 24% share in the cloud infrastructure market, up from 22% in the prior year. That puts Microsoft in second place behind Amazon Web Services, which bodes well for the future. According to Grand View Research, the cloud computing market is expected to grow at 15.7% per year to reach $1.5 trillion.

Over the past year, Microsoft turned in another strong financial performance. Total revenue rose 18% to $198.3 billion, fueled by impressive growth in cloud services and cybersecurity, and free cash flow climbed 16% to $65.2 billion. Despite inflationary headwinds, investors have good reason to believe that momentum will continue.

No company is immune to an economic downturn, but Microsoft is more resilient than most. Not only does its portfolio comprise a number of indispensable software products and cloud services, but the company also has more than $100 billion in cash and short-term investments on its balance sheet.

Also noteworthy, Microsoft pays a quarterly dividend of $0.68 per share, which equates to a dividend yield of 1.16%. That payout has increased each year for the past 13 years, growing at an annualized rate of 13.5%. Microsoft is well on its way to becoming a Dividend Aristocrat, making this stock a particularly attractive option for growth investors looking for passive income. And with shares trading at a reasonable 24.3 times earnings -- a bargain compared to the three-year average of 32.2 times earnings -- now is a good time to buy.