Cathie Wood is the founder and CEO of ARK Invest, an asset management firm focused on disruptive technologies. Wood's investing exploits have been getting a lot of attention lately. Wood's long-term mindset on stocks has helped her company's investments beat the broader market by a wide margin in recent years. In fact, the ARK Innovation ETF (ARKK -0.60%) is up 510% since 2017, crushing the 98% return of the S&P 500 over the same timeframe.

More to the point, Teladoc (TDOC -3.58%) and Tesla (TSLA 5.69%) represent ARK's largest holdings in the ETF, comprising a total investment of $5.7 billion. Given that conviction, investors should take a closer look at these two growth stocks. Here's why I (and Cathie Wood) think Teladoc and Tesla could be long-term winners.

Father and daughter engaging with a physician on the computer.

Image source: Getty Images

1. Teladoc

Teladoc's share prices skyrocketed 138% in 2020 as the COVID-19 pandemic drove up the adoption of telemedicine as a service. But as vaccine efforts have ramped up, the stock price has plummeted, falling more than 50% from its 52-week high in February. The conventional thought, after all, is that once the pandemic is over, the demand for telemedicine will disappear.

But that thinking is wrong. Digitization is upending industries around the world regardless of any pandemic, and healthcare is no exception. In fact, research from the American Psychiatric Association indicates that 43% of people want to continue using telehealth post-pandemic, and 34% said they would prefer virtual visits to in-person appointments.

Teladoc has an advantage there. Its platform is more comprehensive than any other virtual healthcare solution, meaning its clients (i.e. health plans, employers, and patients) can access a wider range of services, from general health and wellness to specialty care like cardiology, dermatology, and pain management.

Last year, Teladoc reinforced that advantage with its acquisition of Livongo, the leader in digital chronic condition management. This move brought specialists in diabetes, hypertension, weight management, and mental health to Teladoc's provider network, further extending its expertise beyond acute care.

The company now has 715,000 patients enrolled in chronic care solutions, a small fraction of its 52 million paid telehealth members. That creates a significant cross-sell opportunity for Teladoc, and investors should expect to see chronic care enrollees rise in the coming quarters.

Here's the bottom line: Telemedicine is a much faster, more convenient, and less costly way to handle non-urgent illnesses like the flu and a more effective way to manage chronic conditions. To that end, Teladoc puts its market opportunity at $250 billion -- more than 150 times its trailing-12-month sales -- leaving plenty of room for future growth. That's why you should consider adding this healthcare stock to your portfolio.

Four Tesla vehicles charging at a Supercharger network location.

Image source: Tesla.

2. Tesla

Tesla's performance in 2021 has been impressive. Despite headwinds in China and a global chip shortage, the company managed to sell 386,100 vehicles through the first half of the year. And Tesla still leads the electric vehicle (EV) industry with a 15% market share.

That feat is even more impressive when considering the company's age. Tesla was founded just 18 years ago, while rivals like Ford Motor and General Motors have been making cars for over a century. So how did Tesla one-up these automotive titans?

Among other things, the company's first-mover status has been a significant edge. Tesla was working on EV technology back when most automakers were still laughing at the idea. And today, Tesla's business is scaling rapidly and efficiently, while its rivals are playing catch-up.

To that point, investors often overlook one aspect of Tesla's first-mover's advantage: the Supercharger network. The company has over 25,000 chargers installed at over 2,700 locations worldwide. By comparison, the next closest competitor is Electrify America, which plans to have 10,000 chargers installed by 2025. That's less than half of Tesla's current infrastructure.

More importantly, CEO Elon Musk recently said Tesla Superchargers will open to other automakers later this year. That may seem trivial, but this move could look brilliant a decade down the road.

First, expanding access to charging stations could hasten the adoption of EVs in general. Second, non-Tesla owners will need to download the Tesla app, meaning Tesla could deliver targeted ads to its rivals' customers -- and what company wouldn't want that advantage? Finally, Tesla will now be able to monetize non-Tesla owners, making as much as $25 billion per year, according to Goldman Sachs analysts.

In all cases, that's good news for the company and its shareholders. And it's one more reason to add this growth stock to your portfolio.