Growth-oriented investors love the tech sector because it's filled with ambitious companies that want to expand across big addressable markets. Many of those companies will fail, but the ones that succeed can generate massive returns for their early investors. Let's take a look at three forward-thinking companies that aren't afraid to take big risks to disrupt older markets: Shopify (NYSE: SHOP), Lemonade (NYSE: LMND), and Square (NYSE: SQ). 1. Shopify: The decentralized e-commerce king Shopify's e-commerce services enable merchants to easily set up online stores, process payments, fulfill orders, and manage their own marketing campaigns. By empowering merchants to build their own e-commerce platforms, Shopify is disrupting the walled gardens of third-party marketplaces like Amazon and eBay. Image source: Getty Images. Shopify now serves over 1.7 million businesses worldwide, and its decentralized network of sellers represents a long-term threat to traditional online marketplaces and brick-and-mortar retailers. Shopify's revenue rose 59% in 2018, 47% in 2019, and 86% in 2020 as more businesses shifted online during the pandemic. Wall Street expects its revenue and adjusted earnings to rise 52% and 9%, respectively, this year, as its momentum continues in a post-pandemic world. Shopify's stock isn't cheap at over 220 times forward earnings and more than 30 times this year's sales. But its early-mover advantage and disruptive growth potential could justify that high valuation. 2. Lemonade: An all-in-one app for online insurance Lemonade's app helps people sign up for home, renters, life, and pet insurance policies on a single platform. It uses AI services and chatbots to streamline the sign-up process, and it can insure users within 90 seconds and process claims and payments in just three minutes. Signing up for insurance policies can be frustrating and time-consuming, especially for first-time buyers. That's why 70% of Lemonade's users are under the age of 35. It recently announced its plans to enter the auto insurance market, and it could provide travel and health insurance plans in the future. Image source: Getty Images. Lemonade's revenue rose more than 11-fold in 2018, nearly tripled in 2019, and grew another 40% in 2020. Its gross loss ratio continually declined over those three years, and its gross margins expanded as it relied more on AI tools and chatbots to cut costs. It expects its gross earned premium, which it calls a better indicator of its growth than its revenue (which is affected by a change to its reinsurance structure in 2020), to grow 70%-73% this year. Lemonade isn't profitable yet, and its stock is also pricey at over 40 times this year's sales. Nonetheless, investors who love great growth stories shouldn't ignore its disruptive potential. 3. Square: A forward-thinking fintech company Square initially disrupted the point of sale (POS) system market with its streamlined payment apps and stand-alone registers. It then expanded its merchant-oriented ecosystem with analytics, marketing, payroll, and financing tools. For consumers, Square offered peer-to-peer payments, Bitcoin (CRYPTO: BTC) purchases, and free stock trades on its Cash App. It also linked those Cash accounts to physical debit cards. Square's revenue rose 49% in 2018, 43% in 2019, and 101% in 2020 as it offset its sluggish growth in seller services revenue with high sales of Bitcoin on its Cash App -- which ended the year with 36 million monthly active customers. It also processed $112.3 billion in gross payment volume (GPV) for the full year, representing 6% growth from 2019. Square's dependence on lower-margin Bitcoin revenue throughout the pandemic squeezed its margins, but that pressure should ease as its merchant-facing businesses recover after the pandemic ends. That's why analysts expect Square's revenue and adjusted earnings to rise 52% and 48%, respectively, this year. Its stock initially looks expensive at 120 times forward earnings, but it also trades at just seven times this year's sales -- which makes it cheaper than many other high-growth tech stocks. 10 stocks we like better than SquareWhen investing geniuses David and Tom Gardner have a stock tip, it can pay to listen. After all, the newsletter they have run for over a decade, Motley Fool Stock Advisor, has tripled the market.* David and Tom just revealed what they believe are the ten best stocks for investors to buy right now... and Square wasn't one of them! That's right -- they think these 10 stocks are even better buys. See the 10 stocks *Stock Advisor returns as of February 24, 2021 John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool's board of directors. Leo Sun owns shares of Amazon, Lemonade, Inc., and Square. The Motley Fool owns shares of and recommends Amazon, Bitcoin, Lemonade, Inc., Shopify, and Square. The Motley Fool recommends eBay and recommends the following options: long January 2022 $1920.0 calls on Amazon, short January 2022 $1940.0 calls on Amazon, and short June 2021 $65.0 calls on eBay. The Motley Fool has a disclosure policy.Source