The Nasdaq-100 technology index is off to a green start in 2023, jumping 5% so far. But after its 33% decline in 2022, the index still has some work to do to claw its way out of bear market territory. It's easy to get caught up in the broader market's gyrations, but investing is more about the health of the underlying businesses you invest in.

A panel of Motley Fool contributors has identified three companies that have been among the fastest growing on the planet over the last three years. They are Bill.com (BILL -0.20%), Confluent (CFLT 0.53%), and CrowdStrike (CRWD 0.22%) -- and despite their stellar revenue growth, each stock is trading at a steep discount to its all-time high at the moment, presenting a unique buying opportunity for investors.

Slashing the admin burden for small businesses

Anthony Di Pizio (Bill.com): Bill.com has earned its spot as one of the fastest-growing companies on the planet thanks to its game-changing tools for small businesses. It has grown its revenue at a whopping compound annual rate of 101% between fiscal 2020 and fiscal 2022, and it's not even close to being done.

Bill.com's flagship product is its cloud-based digital inbox, which manages the accounts payable workflow. It's designed to aggregate a business's incoming invoices, so they're neatly stored online in one place, eliminating messy paper trails. Plus, the business is able to pay those bills with a single click, with the transactions then automatically logged in its bookkeeping software of choice. 

But the company went on an acquisition spree in 2021, buying Invoice2go and Divvy. It means Bill.com can now also provide accounts receivable tools and a budgeting and expense management platform, covering most payments requirements for small businesses. 

Bill.com serves 419,800 customers across its ecosystem, and it expects to generate $1 billion in revenue during the current fiscal year (ending June 30). But that's a mere fraction of its long-term opportunity, because it estimates there are over 70 million businesses in its addressable market, completing $125 trillion in payments annually. 

With Bill.com stock down 70% from its all-time high amid the broader sell-off in the tech sector, this might be a golden opportunity to buy one of the fastest-growing companies on the market at a very steep discount.

A new standard of data processing

Jamie Louko (Confluent): Confluent has been an under-the-radar growth stock, growing its top line at a compound annual rate of 57% over the last three years. Considering the company helps businesses process data in real time to make faster business decisions, it should be no surprise that Confluent is seeing rapid adoption. 

The traditional way businesses analyze data is by processing it in batches on a daily -- sometimes even weekly -- basis. However, many businesses need to take action on the data they receive from their operations immediately, and that's where Confluent's platform comes in. 

Users love the product. In the third quarter of 2022, the number of customers spending over $100,000 per year rocketed 39% higher versus the year-ago quarter to 921. Confluent also posted a net retention rate above 130% for the sixth straight quarter. 

Before 2022, Confluent's primary focus was gaining adoption. The company has pivoted, however, to focus more on profitability. Thankfully for investors, the company is moving in the right direction. The company posted an operating margin under generally accepted accounting principles (GAAP) of negative 78% in its third quarter. Ouch. However, that is still a big step forward compared to the prior-year period when it had a negative operating margin of 92%. Confluent has a long way to go in terms of profitability, but its initial progress is promising. 

Confluent started 2022 trading above 40 times sales, but since then, its valuation multiple has fallen to about 10. Considering how fast the company is expanding and how valuable its services are, it could live up to its current valuation. With shares down this much, now might be the time to buy a small position in this hypergrowth stock.

One of the fastest-growing software companies in history

Trevor Jennewine (CrowdStrike): Cybersecurity specialist CrowdStrike has grown like wildfire over the last three years, with revenue increasing at an annualized rate of 65%. Better yet, the company achieved a $2 billion annual revenue run rate in the second quarter of last year, which makes CrowdStrike the second-fastest software vendor in history to hit that mark. Only Zoom Video Communications got there faster.

Several things are driving that momentum. First, digital transformation and the proliferation of connected devices have left many organizations vulnerable to cybercrime, and resources like ransomware as a service and the dark web have made it easy for cybercriminals to launch sophisticated attacks.

Second, CrowdStrike benefits from a unique platform architecture, superior artificial intelligence (AI), and a broad product portfolio, and those advantages have propelled the company to the forefront of the industry. Specifically, CrowdStrike currently offers 23 different modules that span multiple market verticals. That means businesses can replace disjointed security solutions from multiple vendors with a single integrated platform from one vendor, allowing them to secure endpoints, cloud workloads, identity, and data from single user interface.

Also noteworthy, CrowdStrike designed its platform to crowdsource and gather intelligence from vast quantities of data, which makes its AI models uniquely effective in preventing attacks. As a result, industry analysts have recognized CrowdStrike as a leader in several cybersecurity verticals, including endpoint security, cloud-native application protection, and incident response services.

Currently, CrowdStrike puts its addressable market at $76 billion, but management believes its product roadmap could push that figure to $158 billion by 2026. That underscores an incredible cadence of innovation. In fact, the company just released a new external attack surface management (EASM) product, Falcon Surface. EASM solutions help businesses discover, manage, and monitor their internet-facing assets. Falcon Surface is particularly noteworthy because attack surface expansion is one of the most serious risks that security teams face today, according to research company Gartner.

CrowdStrike has carved out a strong position in the cybersecurity market, and its capacity for innovation should help the company maintain its momentum for years to come. Shares currently trade at 11.2 times sales, near the all-time cheapest valuation since the company went public in 2019. That's why investors should buy this stock today.