Successful investing doesn't have to be complicated. In fact, an incredibly simple strategy of regularly buying shares in the Invesco S&P 500 Equal Weight ETF (RSP 0.70%) every payday could be enough to make you a millionaire by the time you retire.

There aren't many things you can do in life that are quite as straightforward yet can have such a huge impact on your future. It may seem hard to believe, but read on to understand why investing in this ETF right now could make you a millionaire retiree.

Retiree sitting on a deck by a lake.

Image source: Getty Images

What is this ETF?

The S&P 500 is one of the best known U.S. stock market indexes, tracking roughly 500 of the largest publicly traded domestic companies. It's so well known that when people talk about how the market is performing without giving any other qualifier, it often means they're talking about the S&P 500 .

Several funds track the S&P 500 index and provide investors with performance within spitting distance of that definition of the market, as a result. What makes the Invesco S&P 500 Equal Weight ETF stand out is that while it includes all of the S&P 500 companies, it owns a roughly equal proportion of each of those stocks. That's different than most S&P 500 index trackers.

In a more typical S&P 500 index tracking ETF, the fund is weighted by market capitalization -- which means the largest companies in the index have a bigger influence on the fund's performance. That has performed incredibly well in recent years, but it has exposed a potential risk in the index's design. The top 10 holdings now represent over 27% of the index by market capitalization, so if any of those companies should stumble, it'd have a disproportionately huge effect on the index.

Why invest in it?

There are a handful of key reasons to invest in the Invesco S&P 500 Equal Weight ETF. First, it's a bit better diversified than a market capitalization-weighted fund. By owning roughly equal dollar amounts of each of the 500 companies in the index, it's less exposed to the risk of an individual major constituent company slipping up.

There's also a case to be made that the larger a company gets, the harder it is for it to outperform, since each percentage point of growth requires that many more dollars. By putting more emphasis on the smaller companies in the S&P 500, the Invesco S&P 500 Equal Weight ETF is less exposed to that size-related challenge than market capitalization-weighted ETFs.

In addition, as is fitting for an index-related fund, this one benefits from low fees and low churn. That keeps its friction costs low and improves its ability to track its target and return the value its holdings generate to its shareholders.

How much do you have to invest, and for how long, to reach $1 million?

The table below shows how much you'll need to invest each month to reach $1 million, based on the number of years you have ahead of you to invest and various rates of return you may earn. There are no guarantees in the stock market, but over the long run, it has delivered annualized returns somewhere in the neighborhood of 9% to 10%. It's unlikely that long-term returns will be higher than that in the future, so the table shows possibilities at or below that level.

Years to Go

10% Annual Returns

8% Annual Returns

6% Annual Returns

4% Annual Returns




































Table by Author.

If there's one thing abundantly clear from that table, it's that time is your most valuable asset when it comes to retiring a millionaire from this kind of investment. In all those potential return scenarios, the longer your time frame, the less you need to save each month to reach your goal.

So yes -- investing in the Invesco S&P 500 Equal Weight ETF could make you a millionaire by the time you retire. To get there, though, the sooner you get started, the better your chances of success. After all, if you think it's tough to come up with around $200 a month early in your career, imagine trying to start from zero and save roughly $3,000 a month because you waited until later.

What are you waiting for?

You'll never again have more time before you retire than you do right now. Take advantage of the time and money you have available to invest, and put yourself closer to being on track to reaching millionaire status by the time you're done working.

Even if you're not able to invest the full amount you'd need, based on that table, by getting started now, you're putting some money to work for you. That will make it easier to catch up later than trying to start from scratch as a mid-to-late career professional.

Get started now, and see just how close to millionaire status you can get by making regular investments in the Invesco S&P 500 Equal Weight ETF.