When considering which tech stock will produce the largest returns, it's best to invest in innovative companies that will be major players over the next several decades rather than the next few quarters. Amazon (AMZN -1.86%), Apple (AAPL 0.31%), and Microsoft (MSFT -0.47%) have each undoubtedly changed tech as we know it, founded by leaders with an eye sharply trained on the future.

As a result, these companies continue to produce game-changing products and services and are likely to for years to come. Here's why. 

1. Amazon

Amazon revolutionized e-commerce when it was founded in 1994, beginning by selling music and videos, soon moving on to books and hundreds of other products. The company then shook up the industry again with the launch of Amazon Prime in 2005. The subscription service has accumulated 163.5 million U.S. users -- about 49% of the population.

Amazon has earned a reputation for disrupting well-established industries with superior technology and aggressive investment. Its venture into books saw it take on publishers and booksellers worldwide, offering a cheaper and faster way to buy literature. Then, it took on Sony, Apple, and Samsung with its release of e-readers and tablets. Its recent acquisitions of One Medical and iRobot may see Amazon do the same again in the healthcare and consumer robotics industries. 

Moreover, Amazon Web Services (AWS) has become a titan in cloud computing, with a dominating 34% market share of the $203.5 billion industry. Launched in 2006, AWS hosts applications and websites for businesses, universities, and government agencies around the world. As a result, AWS accounted for 13% of Amazon's revenue in the last quarter of 2021 and 100% of its operating income.

Amazon has proven time and time again that it is a force to be reckoned with, no matter the industry. It will likely continue growing and revolutionizing the tech world for years to come. 

2. Apple

Apple is arguably the most innovative company in the world, not necessarily by being the first to introduce a product, but due to its unique talent at reinventing technology and boosting it into the mainstream. In 2007, Apple launched the first iPhone, which catapulted smartphones into the stratosphere and prompted dozens of other tech companies to create similar devices. The tech giant did the same with the tablet when it introduced the iPad in 2010 and convinced millions of consumers to wear a smart watch when it released the Apple Watch in 2016.

Moreover, Apple has developed a winning strategy with its products. Its ecosystem of interconnected devices offers ease of use for consumers and involves a model where users are pulled deeper into its walled garden through just one product. For instance, iPhone users are more likely to seek a MacBook when shopping for a laptop or an iPad when needing a tablet simply because the devices natively work so well together. 

As of Sept. 5, the iPhone overtook Android-powered smartphones in the U.S., reaching 50% market share for the first time. The achievement is positive for Apple because more iPhone users means more people to attract to its other products.

Apple tends to keep a tight lid on its unannounced projects, but rumors have swirled that it has plans to enter various other markets, such as virtual reality, electric vehicles, and folding phones. If the past is anything to go by, these industries will be markedly changed once Apple arrives. 

3. Microsoft 

Since creating Windows software in the 1980s, Microsoft has dominated the desktop and later portable computer market. Despite the best efforts of companies like Apple to capture market share from Microsoft, the maker of Windows has maintained an iron grip on the PC operating system market. Apple has used an aggressive strategy over the last decade, but Windows continues to account for over 76% of the PC software market.

That number rises significantly when it comes to gaming. Windows operating systems make up over 96% of the PC gaming market on the biggest platform, Valve's Steam.

In recent years, Microsoft has been combining its Xbox console and Windows PC gaming businesses. Blurring the lines between the two has led to considerable success with its Netflix-like game subscription service, Xbox Game Pass. The service is the most popular gaming subscription in the world, growing from 10 million members in 2020 to 25 million at the start of 2022. 

As Microsoft aggressively acquires game developers and publishers, the company is in a prime position to lead the future of the gaming industry, much like Netflix did with the movie industry over the last decade. Additionally, its planned acquisition of Activision Blizzard in 2023 will make it the third-largest gaming company by revenue after Tencent and Sony and give it the power to enact further change in the industry.