There's little doubt that investing in high-quality stocks over the long term is the best path to financial independence. Yet there are ways for investors to expedite the process, by finding companies that have the potential to grow their original investment many times over. There are a number of factors that combine in this rare breed of stock that can generate life-changing returns.

Solving an old problem in a new way, getting in on the ground floor of a long-lasting trend, or developing a successful product with a significant addressable market can each be a hallmark of a game-changing investment.

Finding a company that possesses each of those characteristics would certainly increase your chances of success. But what if you could find two such companies and get two for the price of one? Actually, you can. The opportunity? Teladoc Health (TDOC -0.59%).

A woman having a video conference with a doctor on a smartphone.

Image source: Getty Images.

The trend: Telehealth

Telehealth was already gaining steam before the onset of the coronavirus, but with the pandemic continuing to spread rapidly, patients are adopting telehealth like never before. The ability to address medical concerns without a trip to the health clinic or doctor's office is the wave of the future, and no company is better positioned to succeed than Teladoc Health. The company is the global leader in virtual healthcare services, providing app-based video chats with doctors from the comfort of your own home.

The numbers speak for themselves. In the second quarter. Teladoc generated revenue that grew 85% year over year, with subscription revenue that rose 64% and visit-fee revenue that climbed 209%. Some of the underlying trends in the U.S. were even stronger than the numbers suggest, as revenue from paid visits jumped 159%, while revenue from fee-only visits soared 449%. Teladoc's international growth has only just begun, giving the company a long runway for growth. 

The number of patients using telemedicine is soaring as evidenced by the number of visits. Total visits generated by U.S. paid memberships jumped 227% to nearly 1.2 million, while fee-only visits of 306,000 jumped 468%. At the same time, international visits of 453,000 climbed 85%. In all, total visits of nearly 2.8 million grew 203% year over year. 

If that weren't enough reason to buy this game-changing stock, Teladoc has another ace up its sleeve.

A user checking their blood sugar on the Livongo app.

People can check their blood sugar levels on the Livongo app. Image source: Livongo.

A wild-card merger

Teladoc has made a number of acquisitions over the years, but none raised more eyebrows than its plan to merge with Livongo Health (LVGO), which provides a novel, app-based solution that incorporates mobile devices to help patients dealing with chronic conditions.

Estimates vary, but Livongo's management says there are as many as 147 million Americans with at least one chronic condition, including diabetes. The company is working to help these patients by developing strategies and coping mechanisms that result in better outcomes, thereby improving their quality of life and lowering their overall healthcare costs. Livongo uses cutting-edge algorithms and artificial intelligence to detect similarities in patient conditions, then provides customized feedback in the form of suggestions and nudges to help patients stay on track between medical visits. 

The company first tackled diabetes management, but has since added to its lineup to include such diverse conditions as weight management, hypertension, and behavioral health issues (including depression and anxiety), while looking to expand to other use cases.

The success of the Livongo for Diabetes program helps illustrate the potential for these more recent additions. Enrollment grew 113% year over year in the second quarter, propelling revenue of $92 million, up 125%. At the same time, the company's overall client base grew 75%. 

$100 bill with stock market overlay.

Image source: Getty Images.

A large and growing addressable market

Teladoc Health and Livongo Health announced in early August that they would merge to "create a new standard in global healthcare delivery, access, and experience" in a deal worth $18.5 billion. By combining the leaders in virtual care and chronic condition management, the companies believe they will be "uniquely positioned to unlock the full potential of virtual care." The deal is expected to close by the end of the fourth quarter, which is rapidly approaching.

Each company already had an impressive market opportunity, with Teladoc and Livongo citing addressable markets of $30 billion and $34 billion, respectively.  But given the opportunity for cross-selling, upselling, and referrals, the companies now believe their combined addressable market will top $121 billion, and that's just in the U.S. 

To put that number in context, the combined company is expected to generate revenue of just $1.3 billion this year, showing the magnitude of the opportunity that remains.

TDOC Chart

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Is Teladoc and Livongo together a surefire investment?

It's important to understand that while Teladoc and Livongo have been able to generate impressive returns thus far, there's plenty they will have to do right in order for that growth to continue. Additionally, investors need to be willing to pay up for the opportunity. Livongo and Teladoc are currently valued at 38 and 18 times forward sales, respectively, when a price-to-sales ratio of between 1 and 2 is considered reasonable. But given their track record, I'm excited to see what the future holds.

When two proven winners join forces to disrupt the healthcare industry, investors could be among the ultimate beneficiaries.