All large caps started out as small caps. Even a behemoth like Apple debuted on the public markets a few decades ago with a valuation a tiny fraction of its current size, but in the past decade and a half, it delivered massive gains for those shareholders who stuck with it.

Investors, though, have to look forward as they hunt for the companies that might be the next Apple -- potential success stories that could similarly transform themselves from little-known small caps to ubiquitous large caps. Here are two that could do just that.

CuriosityStream's promising future

CuriosityStream (NASDAQ:CURI) is a post-merger special purpose acquisition company (SPAC) that operates a factual streaming service. That's a highly competitive space, but one that is growing at a 20.4% compound annual rate, according to Grand View Research. Based on that, there seems to be room for many winners, and CuriosityStream is proving it can be one.

The company is set to grow revenues by 119% this year to $39.5 million and is forecasting a compound annual growth rate (CAGR) of 72.4% through 2023, which would translate into $202.6 million in sales that year. If management's estimates are accurate, its projected 15% profit margin in 2023 would result in $29.9 million in net income. For a company with an enterprise value of $554 million today, hitting these financial targets would likely lead to meaningful shareholder returns.

While there is certainly no guarantee that any company will meet its long-term financial projections, CuriosityStream's management team is loaded with relevant experience in its industry and deserving of a certain level of trust. The company was founded by John Hendricks -- the creator of Discovery Communications.

Hendricks spent years building that successful factual cable network; now, he's confident he can do the same with CuriosityStream and take advantage of the ongoing shift in the entertainment industry from cable to streaming. He brought with him several former Discovery executives and has been aggressively buying up shares over the last few weeks to express his optimism in the company's prospects.

CuriosityStream has a great deal left to do in order to demonstrate that it can thrive in the current environment. However, if the company can continue to execute, its stock should be a strong investment for years to come.

Lemonade is taking insurance by storm

Hands cupping a bit of soil and a baby plant

Image source: Getty Images.

Lemonade (NYSE:LMND) is a digitally native insurance company that started by offering renters policies, and has since branched out into home, pet, and life insurance. It obsesses over putting the consumer first.

It built a user-interface that leverages artificial intelligence and machine learning to deliver immediate claim fulfillment and plan on-boarding at a growing clip. Furthermore, it takes advantage of the savings that its heavy reliance on AI provides to offer renter's plans at less than half the price that some of its competitors charge for comparable policies. Finally, beyond a certain fee level set in advance, it donates each year's unclaimed premiums to charities of its customers' choosing -- rather than pocketing those dollars like the competition does. This reduces its motivation to deny claims, because the company won't be keeping the excess.

All of this translates into a comparatively high net promoter score, and a rapidly growing business.

In its most recently reported quarter, Lemonade's total premiums grew by 99% year over year to $188.9 million, and its customer base grew by 67% to 941,313. While it is not yet profitable, the company is moving in the right direction with adjusted EBITDA as a percentage of total premiums improving from negative 32% to negative 14.6%.

The company frequently reiterates its desire to branch out into new insurance offerings as well as expand geographically to other nations such as France. It has built a best-in-class user interface. Now, it can leverage that tool to debut more and more products -- and that's the plan.  It should provide a meaningful runway for continued long-term growth.

Worth a small investment

Both CuriosityStream and Lemonade offer investors both explosive potential upsides and meaningful downside risks. Considering this, I think a small investment in both should be considered. But that's all you'd need in order to realize significant returns if either or both continue to execute over the long term.