If you thought the baby boomers knew how to run an economy, just wait until the millennials take their place. More than 90 million young Americans fit that label, and the boomers stopped short at just 77 million.

This is a cultural sea change, driving huge differences in how Americans make, manage, and spend their money. With that in mind, young investors are placing their first stock orders in the middle of a missive market change. So, we asked a few of the best investors here at The Motley Fool how millennials should get started in the stock market.

Our panelists pulled out their big guns for this one. Read on to see why they recommend young Americans to invest in household names Amazon.com (NASDAQ:AMZN)JPMorgan (NYSE:JPM), and Facebook (NASDAQ:FB).

A group of young men and women discussing a presentation on a laptop.

Image source: Getty Images.

Amazon was built just for you

Anders Bylund (Amazon.com): Millennials are more price-sensitive than earlier generations of Americans. They also care a lot about convenience, whether they're looking for a complete online shopping experience or a large catalog of schedule-free TV shows. Oh, and they are also known as the first generation of "digital natives," for whom online services feel as natural as their old-school bricks and mortar equivalents.

You just read the basic business idea behind Amazon. The company offers low-cost shopping and high-quality digital services in a variety of markets. Founder and CEO Jeff Bezos started with a simple online bookstore, expanded into other retail opportunities as Amazon grew, and then tacked on new-age products like Amazon Prime Video and Amazon Web Services along the way. This company caters directly to millennials in every way.

That's a smart strategy, because you're looking at a massive cohort of 92 million Americans who were born between 1980 and 2000. The youngest of these newly minted consumers turned 17 this year and will join the workforce very soon. At the other end of the age spectrum, some millennials are going through their midlife crises and entering the highest-earning years of their lives. Even if some older Americans might not get what Amazon is about, this demographic is strong enough to support an army of online businesses -- with Amazon leading the charge. Invest in what you know, they say. Young investors are already on a first-name basis with Amazon.

Amazon is also a fantastic investment today. It's more than just an effective cash machine; it's also a fast-growing business with a yen for innovation. The house that Bezos built will stick around for decades, making it a great choice for young investors with long-term goals in mind.

Like, you know, most millennials.

What you can earn and what you can learn

Jordan Wathen (JPMorgan Chase): Investing in individual stocks is about more than just what you can earn; it's also about what you can learn. It's my view that JPMorgan Chase is an excellent stock to own for both reasons.

As the largest bank in the United States, JPMorgan has its hands in everything from small business banking to trading and asset management. That scale gives it the ability to be a leader in cost efficiency, cross-selling, and risk management, traits that underlie its top-tier performance since its CEO, Jamie Dimon, took the helm in 2005. It also gives JPMorgan incredible insight into the American economy.

Dimon uses his platform as the CEO of the United States' largest bank to explain, in layman's terms, what matters (and what doesn't) in the banking and financial universe. His annual shareholder letters are to the banking industry what Warren Buffett's letters are to insurance and investment management.

To understand a bank, you'll have to understand the movements of interest rates, or the performance of certain corners of the economy (last year, it was all oil and gas; this year, every bank is focused on retail and retail real estate). Thus, I view investing in a bank -- even if it's just one share -- as a really good way to keep tabs on what's going on in the economy as a whole.

Priced at about 14 times earnings and two times tangible book value, JPMorgan won't set the world on fire when it comes to returns. But I think it's likely that the stock could produce market-beating returns over the long haul -- and be a great building block stock for investors who want to learn more about what's going on in the financial world.

Facebook's iconic logo, white on a blue field.

Image source: Facebook.

There's a lot to like about Facebook

Keith Noonan (Facebook): Millennials have sometimes been referred to as "The Facebook Generation," and while that moniker seemingly downplays the social network's cross-age appeal, there's no denying that many in the generation are deeply familiar with the platform and have played a role in its incredible success. By investing in the company, they also have the opportunity to benefit from its ongoing growth.

Facebook's rise over the last has 12 years has changed the world, and while the company currently trades near all-time highs, it's still a stock that has the potential to deliver tremendous returns over the long term and help investors reach their financial goals. A forward P/E value of roughly 31 might deter some investors, but unless you're particularly risk-averse, I don't think that it should. Facebook continues to deliver rapid growth, with sales up 47% year over year in the last quarter and net income up a whopping 71%. And, even as the stock has gained nearly 50% year to date, its forward price-to-earnings-growth ratio is just 0.6.

In June, the company recorded 2.01 billion monthly active users and 1.32 billion daily active users. Those types of user metrics point to Facebook continuing to benefit from a tremendous network effect, and its Instagram and WhatsApp subsidiaries are also recording impressive engagement levels and are still in comparatively early phases of being monetized. With Facebook seemingly poised to retain a dominant position in the fast-growing social media space, its stock has the potential to be a big winner for millennial investors.

Anders Bylund owns shares of Amazon. Jordan Wathen has no position in any of the stocks mentioned. Keith Noonan has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Amazon and Facebook. The Motley Fool has a disclosure policy.