Remember the meme-stock craze that happened in 2021? Many stocks rocketed higher for no apparent reason, in some cases doubling, tripling, or much more in just a few days.

Many so-called meme stocks are not great businesses. In fact, some of the most high-profile meme stocks have declared bankruptcy recently. On the other hand, some could be excellent long-term investments if they can execute on their tremendous market opportunities.

A true banking disruptor

There's no shortage of financial technology companies that have created disruptive alternatives to traditional banking products. For example, there are apps that make investing easier than ever before, and plenty of online-based banks offer savings accounts with annual percentage yields (APYs) that branch-based banks can't match. But none have successfully become all-in-one banking disruptors that can completely replace a customer's existing bank relationship.

SoFi (SOFI 3.69%) is a different story. It offers checking and savings accounts, credit cards, loans, brokerage accounts, and much more, all in one user-friendly and low-fee platform. It has scaled rapidly to 6.24 million members and grew 44% year over year in the second quarter. The bank's net interest margin of 5.74% far exceeds its peer-group average, and the deposit platform has grown from zero at the beginning of 2022 to $12.7 billion today.

The bank could be just getting started, as it's still a relatively small institution. With about $25 billion in assets, SoFi is about the same size as City National Bank of Florida or Beal Bank USA. If you just said, "Who?" -- well, that's the point. SoFi is still in the early stages, but its momentum is undeniable.

An industry that's begging for disruption

Let's face it -- dealing with insurance companies is a clunky process, at best. The claims process is often confusing and lengthy, applying for insurance can be a hassle, and it can be extremely difficult to get help when you need it.

Lemonade (LMND 1.64%) has done an excellent job of creating a top-notch customer experience. It started with renter's insurance but has since expanded to homeowners, pet, life, and most recently, auto insurance, which is still in the early stages of rolling out.

Over the past three years, Lemonade has grown its customer base by 69%. And thanks to focusing on higher-premium types of insurance, its in-force premium has increased by 160% in that time.

There are still some big unanswered questions when it comes to profitability. The company's 87% gross loss ratio is far above its 75% target, and the business posted a $66 million net loss in the first quarter alone.

With nearly $1 billion in cash and equivalents on its balance sheet, the company has plenty of runway to figure out the profitability question. Investors, however, will want to see those losses start to narrow and its underwriting to start improving as the business continues to scale.

Don't expect a smooth ride

As the headline suggests, I truly believe both of these stocks have legitimate long-term upside. In fact, I own both in my own stock portfolio.

However, if you invest in these stocks -- or any companies still in the relatively early stages of capturing their addressable markets -- it's wise to expect a bumpy ride. Even if things go well, these stocks aren't likely to go up in a straight line, and even small negative news items can create quite a bit of turbulence. Invest with that in mind.