Many growth-oriented investors dream of finding the next great multibagger stock that can turn a $50,000 investment into $1 million. But finding that next millionaire-maker stock requires a keen eye for spotting disruptive trends -- and sticking with your investment through market downturns requires a strong stomach.

Today, let's focus on five high-growth tech companies that might generate millionaire-maker returns over the next two decades: Lemonade (LMND -0.77%), Affirm (AFRM -0.07%), Square (SQ -0.42%), Robinhood (HOOD -1.18%), and Pinterest (PINS +0.96%). All five of these stocks are volatile, but their underlying businesses could all generate massive growth with their disruptive platforms.

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1. Lemonade

Lemonade aims to disrupt the byzantine insurance market with an AI-powered app, which insures users within 90 seconds and processes claims within three minutes. It already offers renters, homeowners, term life, and pet insurance, and it plans to launch auto insurance in the near future.

Lemonade's streamlined approach has made it popular with younger and first-time insurance buyers, and it ended last quarter with 1.21 million customers, up 48% from a year earlier. It's still unprofitable, but its gross earned premium, premium per customer, and retention rates are all rising.

Lemonade still faces threats like tech-forward competitors and climate change, but it could still generate multibagger returns if its platform gains tens of millions of new customers over the next few years.

2. Affirm

Affirm offers buy now, pay later (BNPL) services that enable merchants to break down larger purchases into smaller monthly payments. Affirm believes this approach will disrupt traditional credit card companies, which usually charge retailers "swipe fees" of 1% to 3%.

Affirm ended its most recent quarter with nearly 29,000 active merchants, up 412% from a year ago, while its active customers nearly doubled to 7.1 million. Those numbers are still tiny compared to the 2.8 billion credit cards in use globally, but Bank of America expects the market for BNPL apps to expand up to 15 times by 2025.

Affirm is still unprofitable and suffers from customer concentration issues, but its recent deals with Shopify and Amazon could allow it to reach millions of new merchants and customers. That long-term growth could spark some huge gains for Affirm's stock.

3. Square

Square initially disrupted the point-of-sale (POS) system market with its card-swiping dongles, mobile apps, and stand-alone registers. It subsequently launched an ecosystem of cloud-based seller services to help businesses manage their payrolls, open online shops, and even take out loans.

Square is now disrupting traditional banks by providing peer-to-peer payments, Bitcoin trades, and free stock trades on its Cash App. It also plans to take on Affirm with its upcoming purchase of Afterpay, an Australian leader in BNPL services.

Simply put, Square plans to become the bank of the future, with a growing ecosystem of over 2 million sellers, 210 million buyers, and 40 million monthly Cash App users. Therefore, it could generate much higher revenue by 2040 as it gains a new generation of mobile-first savers, payers, and investors.

4. Robinhood

Another fintech disruptor to watch is Robinhood, which shook up the traditional brokerage market with free stock and cryptocurrency trades. It funds its free trades by selling its clients' order flows to market makers, which profit off the bid-ask spreads on each trade.

Robinhood's business model is controversial, but its growth is impossible to ignore. It ended last quarter with 21.3 million monthly active users (MAUs), more than doubling from a year ago, and most of its MAUs are younger investors between the ages of 18 and 40.

By comparison, Charles Schwab, one of the largest brokerage houses in the United States, hosts 32.4 million active brokerage accounts. Schwab's rival Fidelity serves 38 million investors. If Robinhood continues to grow and pull investors away from those older brokerage houses, it could become a fintech powerhouse like Square -- and its stock could soar much higher.

5. Pinterest

Pinterest carved out a high-growth niche in the crowded social networking market with its virtual pinboards, which enable users to pin and share their hobbies and interests with other users. Many retailers have uploaded their entire catalogs to Pinterest's pinboard as shoppable pins, giving it an early mover's advantage in the nascent "social shopping" market.

Pinterest served 454 million MAUs last quarter, up 9% from a year earlier, and its average revenue per user (ARPU) continues to rise. Yet Pinterest's stock price tumbled last month as investors fretted over its sequential decline in MAUs and expectations for a slowdown in a post-pandemic world.

But Pinterest mainly lost slow-growth desktop users instead of its higher-growth mobile users, and its future beyond the pandemic still looks bright. Over the next few decades, social platforms will likely merge with e-commerce ones -- and Pinterest could be a top destination for those shoppers. Therefore, I believe this $35 billion social networking company could still grow much larger by 2040.