Becoming a multimillionaire investor is easier than you may think. You don't need to know all the ins and outs of the stock market or have a lot of money to invest. All you need is a strategy.

Investing in growth ETFs can be a smart move to maximize your earnings. A growth ETF is a collection of stocks that have potential for rapid growth. They tend to be higher risk than broad-market funds, such as S&P 500 index funds. However, they also generally see greater returns.

Not all growth ETFs are created equal. These three, in particular, have higher-than-average rates of return, and they can help you reach multimillionaire status.

Large pile of hundred dollar bills

Image source: Getty Images.

1. Vanguard Growth ETF (VUG)

The Vanguard Growth ETF (NYSEMKT:VUG) contains 257 stocks from high-growth companies. Some of the largest companies in the fund include Apple, Microsoft, Amazon, and Google's parent company Alphabet.

Since its inception in 2004, this ETF has earned an 11% average annual rate of return. At that rate, here's how you could become a multimillionaire:

  • Invest $500 per month for 35 years = $2 million in total savings
  • Invest $900 per month for 30 years = $2.2 million in total savings
  • Invest $300 per month for 40 years = $2.1 million in total savings

It takes time to accumulate a significant amount of money with ETFs, but that patience will pay off. Keep in mind, too, that these investments require very little upkeep. All you need to do is invest consistently, then sit back and wait for your investments to grow.

2. Vanguard Information Technology ETF (VGT)

Like the name suggests, the Vanguard Information Technology ETF (NYSEMKT:VGT) contains stocks from the information technology field. It includes 345 stocks from companies such as Apple, Microsoft, NVIDIA, and Visa.

This fund carries slightly more risk than the Vanguard Growth ETF because it only contains stocks from one sector. However, it's also experienced higher returns of 13% per year since its inception in 2004. At that rate, here's how you could become a multimillionaire:

  • Invest $300 per month for 35 years = $2 million in total savings
  • Invest $600 per month for 30 years = $2.1 million in total savings
  • Invest $200 per month for 40 years = $2.4 million in total savings

The more you're able to invest and the longer your timeframe, the more you can earn. For example, if you were able to invest $600 per month for 40 years while earning a 13% annual return, you could potentially save an incredible $7.3 million.

Jar full of hundred dollar bills

Image source: Getty Images.

3. ARK Fintech Innovation ETF (ARKF)

The ARK Fintech Innovation ETF (NYSEMKT:ARKF) is a high-risk, high-reward type of investment. It typically holds between 35 and 55 stocks, so it doesn't provide as much diversification as the other two funds.

It also only contains fintech stocks, which are generally riskier but also have higher potential for reward. A few of the largest companies within the fund include SquarePayPal, and Zillow. The fund is also younger than the others on the list, as it was established in Jan. 2019.

That said, it has experienced a remarkable couple of years. Since its inception, it has earned a whopping 62% annual rate of return. Here's what you'd need to save to become a multimillionaire:

  • Invest $100 per month for 15 years = $2.6 million in total savings
  • Invest $400 per month for 12 years = $2.5 million in total savings
  • Invest $50 per month for 17 years = $3.5 million in total savings

Of course, it's unrealistic to expect to earn a 62% return year after year. But even if you were earning returns of, say, 20% per year, you could still reach $2 million in savings if you were to invest around $350 per month for 25 years.

Again, this fund is the riskiest on the list. Only invest in this fund if you have a relatively high tolerance for risk, and be sure you have a well-diversified portfolio to fall back on just in case this ETF doesn't perform as well as you expect.

Becoming a multimillionaire investor is possible, but you'll need a strategy. By investing in the right places and being patient as your money grows, you'll be well on your way to getting rich in the stock market.

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.