If you want to achieve significant gains in the stock market, you'll probably want to plan to hold on and remain invested for many years, or even decades. But in some cases, big payoffs can come much faster than that. The benefit of investing in growth stocks is that they have the potential to deliver some terrific returns.

For example, growth stocks Strategy (MSTR 0.68%), Mara Holdings (MARA -0.19%), and Verona Pharma (VRNA 2.50%) have yielded fantastic gains for investors over the past five years. If you had invested $15,000 into each one of these stocks just five years ago and held on, you would have a portfolio worth more than $1 million today. The question is, do they still have the potential for further significant gains for investors who buy them right now?

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Strategy

A $15,000 investment made five years ago into the company that at that time called itself MicroStrategy would now be worth around $458,000. That's a staggering return when you consider that its core technology business hasn't been taking off. The company, which earlier this year shortened its name to Strategy, has actually experienced a decline in revenue in recent years. While it's nominally involved in providing business intelligence solutions, the reason its stock skyrocketed was tied to its aggressive moves in the cryptocurrency space.

Strategy is the largest corporate holder of Bitcoin (BTC -0.42%), with a stash that now totals more than 500,000 coins. The company routinely updates investors on its position and Bitcoin holdings. Executive Chairman Michael Saylor is incredibly bullish on the popular digital currency's potential value, predicting that its token price will climb to well over $1 million in the future, and suggesting that it could potentially top $13 million by 2045.

Strategy stock could still rise higher if Bitcoin does well. But it's a highly speculative buy: Its valuation is not tied to its overall performance, but is instead contingent on how strong the crypto market is. If you're bullish about that, you may feel that the stock could be a good buy. But for the majority of investors, this investment is likely to be too risky and speculative to hold.

Mara Holdings

Bitcoin mining company Mara has also benefited from the cryptocurrency's rising value over the past five years. During that stretch, a $15,000 investment into the stock would have grown into a holding worth approximately $290,000. Remarkably, that result includes a steep drop that it hasn't fully recovered from yet: The crypto stock is down by more than 50% from where it began 2022.

In the past three years, the company's bottom line has fluctuated drastically, from a loss of more than $694 million in 2022 to a profit of $541 million in 2024, and the stock has been similarly volatile. Its performance inevitably hinges on the changes in the market value of the digital assets it mines and holds.

As with Strategy, this is a speculative buy, as Mara's valuation will ultimately depend on how well Bitcoin is doing. This isn't a stock I'd suggest owning unless you have an extremely high risk tolerance.

Verona Pharma

The only stock on this list that hasn't amassed its gains due to crypto is Verona Pharma. However, the biopharmaceutical company has still generated impressive returns for investors. A $15,000 investment in the business five years ago would now be worth $267,000. Add that to the gains from your hypothetical $15,000 investments in the other two companies mentioned, and you'd have around $1.02 million.

Shares of Verona started to take off in June 2024 after the company obtained Food and Drug Administration approval for Ohtuvayre as a maintenance treatment for chronic obstructive pulmonary disease. Analysts believe Ohtuvayre can become a blockbuster drug, generating more than $1 billion in annual revenue for Verona by 2029.

Verona incurred a loss of more than $173 million last year, but with Ohtuvayre already beginning to generate sales, the business is on a much more positive trajectory. The stock's valuation isn't cheap, as its market cap is hovering around $7 billion. But given its promising growth prospects and its possible path to profitability, it's the only stock on this list that I'd consider buying today.