Given the year we've had in 2020, it wouldn't surprise me if folks thought it difficult to make money investing in the stock market. After all, we've witnessed record-breaking volatility, as measured by the CBOE Volatility Index, and a peak 34% loss in the benchmark S&P 500 over a roughly one-month time frame.

But historical data suggests otherwise. Over the long run, the S&P 500 has returned 7% annually, inclusive of dividends paid. This factors in the dozens of corrections and bear markets the widely followed index has navigated its way through over the years.

In other words, it's easy to get rich investing in the stock market, as long as you follow a simple recipe for success: Buy innovative stocks and hang onto them over the long haul.

If you have, say, $2,500 that can be invested right now, which won't be needed to cover bills or emergencies, you have more than enough to take a stake in the following three highly innovative companies.

A clock and digital quote board superimposed on a pile of cash and stacks of coins.

Image source: Getty Images.

Square

I was skeptical that Wall Street's third-quarter expectations for fintech stock Square (NYSE:SQ) were overly optimism. Apparently, they weren't even close to high enough, demonstrating what a powerhouse this payment facilitator is quickly becoming.

Square is best-known for the company's seller ecosystem, which provides point-of-sale devices and analytics tools for businesses. Prior to 2020 and the coronavirus disease 2019 (COVID-19) pandemic completely disrupting traditional retail, Square's seller ecosystem had been growing by an average of 49% annually since 2012.

This merchant-fee-driven segment has been predominantly used by smaller businesses for years. But what's particularly interesting is that bigger businesses are now adopting Square's payment platform in greater numbers. In the third quarter, 61% of gross payment volume (GPV) was derived from businesses generating $125,000 or more in annualized GPV. That's up 8 percentage points from the same quarter two years ago. 

However, it's digital peer-to-peer payment platform Cash App that continues to amaze investors. Square revealed 30 million monthly active users, as of June 30, with this total almost certainly rising since then. What really stands out from the company's third-quarter report is that nearly a quarter of monthly Cash App users are using the application daily. That's up from 15% in Q3 2018. Cash App usage for investments and merchant activity is picking up in a big way -- so much so that Cash App likely becomes Square's primary profit driver in 2021.

Square has all the tools necessary to make its shareholders rich.

A family seated on a couch, with the family dog in the middle.

Image source: Getty Images.

Trupanion

Generally speaking, insurance isn't exactly an innovative industry. But when we're talking about an insanely underrepresented market -- companion animals -- a company like Trupanion (NASDAQ:TRUP) stands out as a game-changer.

According to data from the American Pet Products Association, close to 85 million households in the U.S. owns a companion pet, with an estimated $99 billion expected be spent on those pets this year. Of this $99 billion, approximately $30 billion will be derived from veterinary care and product sales. With an overwhelming number of pet owners viewing their dog or cat as a family member, it's not a surprise that they'll spend big bucks to ensure their health and well-being. 

Trupanion steps in as a provider of companion pet health-benefit policies throughout North America. It's been able to penetrate (drumroll) just 1% to 2% of the North American companion pet market, yet is consistently seeing double-digit year-on-year sales growth. In the recently ended third quarter, Trupanion's sales jumped 31% from the prior-year period, with total enrolled pets increasing by the same percentage.  Essentially, the growth runway for this company spans many years.

It's worth noting that Trupanion's business model is built atop subscriptions. That's important, because subscriptions generally lead to high-margin, predictable, and transparent revenue. It also helps to reduce the possibility of customer churn.

Also, don't overlook that Trupanion has spent the last 20 years developing rapport with veterinarians at the clinical level. Vet offices and veterinarians are Trupanion's voice, and they're going to play a key role in supporting the company's double-digit growth rate.

An engineer plugging wires into the back of a data center server tower.

Image source: Getty Images.

Fastly

Another innovative stock that can make shareholders rich over the long run is content-delivery specialist Fastly (NYSE:FSLY).

Over the past month, the only thing that's been happening "Fastly" is the decline of this company's share price. Fastly warned in October that declining revenue from TikTok, the company's top customer in the first-half of the year (12% of first-half sales), would cause revenue to come in at $70 million to $71 million, down from a prior forecast of $73.5 million to $75.5 million.

While this revenue revision was less than ideal, Fastly is far more than just TikTok, as evidenced by the company's third-quarter earnings release. The company tacked on another 95 customers, saw its average enterprise client increase its quarterly spend by $37,000 from the sequential second quarter, and delivered a dollar-based net expansion rate of 147%. In short, Fastly's existing client are spending more with the company, which is really helping to push margins higher. Spending at TikTok may be down substantially, but its other clients are picking up their usage big-time. 

It's also important to realize that Fastly's growth isn't fleeting. In other words, while the shift online by businesses and consumers has been accelerated by the COVID-19 pandemic, this was a trend we were seeing well before the pandemic hit. Even with the coronavirus pandemic is under control, Fastly's position as the preferred edge cloud platform will remain secure, and usage should be on the incline.

Investors should look for Fastly to triple its annual sales over the next four years.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.