Investing in the stock market can definitely make you a millionaire -- if you have enough time and/or you invest significant sums. Over 25 years, for example, you can amass almost $1.2 million by saving and investing $15,000 annually and earning an average annual return of 8%. That's terrific!

But if you want to get to millionairehood faster, you could take on more risk by investing in some individual stocks -- perhaps while keeping a chunk of your assets in some solid low-fee index funds. There's no guarantee of great returns, but plenty of stocks have the potential to double and triple over the coming years.

Here are three stocks to consider for your long-term portfolio -- ones that might help you become a millionaire faster.

We see the back of a seated man with a cigar looking out over the night lights of a city.

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1. Jushi Holdings

You may have noticed that medical and recreational marijuana has become legal in more and more states over the past decade or so, with the trend likely to continue. Thus, there's understandably a lot of interest in marijuana-focused companies as potentially powerful investments. There are a lot of such companies, though, so it can be confusing figuring out which are best positioned to prosper. One company that has a lot of advocates is Jushi Holdings (OTC:JUSHF).

Based in Boca Raton, Florida, Jushi is "a national, multi-state cannabis company developing and operating high-end retail locations, premium brands and state-of-the-art cultivation, processing and manufacturing facilities." It recently had 16 open stores and 16 more opening, in a handful of states such as California, Pennsylvania, Illinois, and Virginia.

One of the nice things about Jushi is that though its stock has more than sextupled in value over the past year, it's still a modestly sized enterprise, with a recent market capitalization of just $790 million. In other words, there's plenty of room for growth. Another big plus for the company is that its insiders have invested tens of millions of dollars of their own money in the company, meaning that they have considerable skin in the game and are very motivated to make the company succeed.

2. Boston Omaha

Boston Omaha (NASDAQ:BOMN) is another smallish company, with a recent market value of $1.2 billion. It's a bit of an unusual company, too, sometimes likened to Warren Buffett's Berkshire Hathaway -- though it doesn't have Berkshire's decades-long amazing track record nor Buffett at its helm. (His grandnephew, Alex Rozek, is its co-CEO, though.)

The similarity with Berkshire stems from the fact that Boston Omaha is diverse in its operations. Its three majority-owned businesses are focused on outdoor advertising (think billboards), surety insurance, and broadband telecommunications. Like Berkshire, it also has other interests, such as minority ownership positions in a bank, a national residential homebuilder and commercial real estate services businesses. One of those businesses recently had an IPO, leaving Boston Omaha with shares recently worth tens of millions of dollars.

One reason that some investors are newly excited about Boston Omaha is that it has recently launched a "SPAC," or special-purpose acquisition company -- a business that's often referred to as a "blank check company," because it takes money from investors to buy other companies -- on a "trust me, I'll buy good businesses" basis. Boston Omaha is well worth a closer look, if your interest is piqued.

A road sign says millionaire next exit.

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3. Universal Display

Finally, we come to Universal Display (NASDAQ:OLED), a $10.5 billion tech company that has seen its shares nearly quadruple in value over the past five years. It specializes in technology for energy-efficient organic light-emitting diode (OLED) lighting, which is found in many, if not most, smartphones.

The technology for OLED lighting is developing and improving, and Universal Display is a major player in researching and developing it. It owns or has the right to sublicense more than 5,000 patents (both issued and pending), and it gets 43% of its revenue (in 2020) from just that -- licensing. It's not a manufacturer of OLED products, but it does sell the materials for them, and those sales are where 54% of its revenue came from in 2020.

One promising catalyst for Universal Display's growth is that more televisions are being produced with OLED screens, and those take up a lot more real estate than a small smartphone screen, so they'll require more production materials. This profitable company seems reasonably valued, too, with both its regular and forward-looking price-to-earnings (P/E) ratios on the steep side, but also below their five-year averages. And it even pays a small (but growing) dividend.

Each of these three companies seems poised to perform well over the coming decade or so, and they could hasten your arrival at millionairehood -- or could just help a portion of your portfolio grow more briskly. Take a closer look at any that interest you.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.