Economic uncertainty sent the Nasdaq Composite spiraling into a bear market this year, and many excellent growth stocks fell sharply during the stock market meltdown. For instance, Microsoft (MSFT -0.14%) and MercadoLibre (MELI -3.27%) saw their share prices plunge 28.2% and 24.3%, respectively, in 2022. But there is a silver lining for long-term investors.

Shares of Microsoft and MercadoLibre have fallen more sharply during the current bear market than at any other point in the past 10 years, creating a once-in-a-decade buying opportunity. More importantly, both companies are well-positioned to create value for shareholders in the coming years.

Here's why.

1. Microsoft: Business productivity software and cloud services

Microsoft turned in a series of respectable financial results over the past year. Revenue climbed 15% to $203 billion on a trailing-12-month basis, and free cash flow rose 5% to $63 billion. Unfortunately, management expects economic headwinds to weigh on its Windows and advertising businesses in the near term, so financial guidance for the second quarter of fiscal 2023 (which ends Dec. 31) fell short of Wall Street's forecast.

Many traders took that as a sell signal, but long-term investors need to look at the big picture. Brand Finance named Microsoft the fourth-most-valuable brand in the world in 2022, and it ranked CEO Satya Nadella as the top business leader. Collectively, immense brand authority and a strong CEO made Microsoft a key player in several important industries.

The company is perhaps best known for its productivity suite, Office 365, but it also has a strong market presence in other software verticals, including enterprise resource planning, business analytics, communications, and low-code development.

Better yet, Microsoft is a leader in several categories of the cybersecurity industry, and its security revenue soared 40% in fiscal 2022 (ended June 30). That metric is particularly exciting because global cybersecurity spending is expected to rise 12% annually to reach $500 billion by 2023, according to Grand View Research. That means investors can reasonably expect Microsoft to grow security revenue at a double-digit pace through the end of the decade.

Meanwhile, Microsoft Azure is the second-most-popular cloud services provider, and its expertise in developer tools, database solutions, and artificial intelligence applications are strong growth drivers. In the most recent quarter, Azure and other cloud services collectively achieved 35% revenue growth. But Grand View Research says the cloud computing market will expand at 16% annually to reach $1.6 trillion by 2030. That means investors can reasonably expect Azure to grow at a double-digit pace through the end of the decade.

Microsoft currently trades 8.9 times sales, a very reasonable valuation for a company with a good shot at double-digit sales growth for years to come. That's why this growth stock is worth buying today.

2. MercadoLibre: E-commerce and financial services

In 2022, Latin America will be the world's second-fastest-growing region in terms of e-commerce sales, according to eMarketer, and MercadoLibre is the clear leader in that region. Its online marketplace receives more unique visitors and more page views than any competing platform in every major country where it operates. In fact, MercadoLibre sees nearly four times as many monthly visits as its next closest competitor. That alone is a compelling value proposition for merchants, but the company made its marketplace even stickier with adjacent services like logistics, credit, and digital advertising.

MercadoLibre also provides merchant-facing payment processing and consumer-facing digital wallet services through its fintech platform Mercado Pago. Thanks to the low bank account and debit card penetration among Latin American consumers, its fintech business is growing like wildfire. In fact, Mercado Pago ranks as the third-most-popular digital wallet in the region, and off-platform payment volume has increased at a triple-digit pace for the last four quarters. That means Mercado Pago is quickly gaining momentum beyond the MercadoLibre marketplace.

Despite a challenging economic climate, the company reported impressive financial results in the third quarter. Revenue increased 45% to $2.7 billion -- representing 20% growth in the commerce business and 94% growth in the fintech business -- and GAAP earnings climbed 33% to $2.56 per diluted share.

Looking ahead, investors have good reason to believe that momentum will continue for years. The MercadoLibre marketplace powered $28.4 billion in e-commerce sales in 2021, but online retail sales in Latin America will reach $167 billion this year, according to eMarketer. Similarly, Mercado Pago handled $77.4 billion in total payment volume in 2021, but digital payment volume in Latin America will reach $252 billion this year, according to Statista. Better yet, both markets are growing at a double-digit pace, creating a long runway for future growth.

MercadoLibre stock currently trades at 5 times sales, an absolute bargain compared to its three-year average of 13.2 times sales. That's why investors should jump on this buying opportunity.