How I'd aim to build a $1 million ASX share portfolio in 20 years

Regular investing and time can add up to something substantial.

| More on:

You’re reading a free article with opinions that may differ from The Motley Fool’s Premium Investing Services. Become a Motley Fool member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn More

Building a $1 million share portfolio can sound like a goal reserved for people starting with a lot of money.

But time and consistency can change the picture considerably.

If I were aiming for that target over the next 20 years, this is how I would approach it.

Happy girl holding a plant and soil in front of ascending piles of coins.

Image source: Getty Images

Start with $20,000 and keep adding

Let's assume I begin with a $20,000 ASX share portfolio and invest another $1,500 each month.

That works out to $18,000 of new money every year.

If the portfolio produces an average return of around 9% per annum, those contributions could grow to approximately $1 million over 20 years.

I should point out that there are no guarantees the market will deliver 9% annually. Returns will vary considerably from year to year, but 9% is roughly in line with the historical average annual return.

I think this example shows why I would focus less on finding one spectacular investment and more on keeping money invested for a long time.

I would also reinvest dividends where appropriate and give successful investments time to grow rather than constantly trading in and out of the market. This will allow compounding to do its work.

Focus on quality businesses

If I were choosing individual ASX shares, I would want companies capable of becoming more valuable over many years.

That means looking for strong competitive positions, healthy balance sheets, capable management, and genuine opportunities to keep growing.

This could mean ASX shares like Goodman Group (ASX: GMG), Cochlear Ltd (ASX: COH), TechnologyOne Ltd (ASX: TNE), and Macquarie Group Ltd (ASX: MQG).

The goal would not be to predict which share performs best next month. I would be trying to assemble a collection of businesses capable of compounding earnings and value throughout much of the 20-year period.

Diversification would also be important. It is worth remembering that even businesses that look excellent today can disappoint. So, having a portfolio with sufficient diversification could offer some downside protection.

Consistency could be the biggest advantage

I think the $1,500 monthly contribution into ASX shares is just as important as the return assumption.

There will inevitably be periods when markets fall sharply and investing feels uncomfortable.

Those could actually be some of the most valuable months to keep contributing, because the same $1,500 buys more shares at lower prices.

Foolish takeaway

I would not expect the journey to $1 million to be smooth.

But starting with $20,000, investing $1,500 each month, and targeting a long-term return of around 9% gives the goal a realistic foundation.

For me, the strategy comes down to three things: quality investments, consistent contributions, and enough patience to let compounding do its work.

Motley Fool contributor Grace Alvino has no position in any of the stocks mentioned. The Motley Fool Australia's parent company Motley Fool Holdings Inc. has positions in and has recommended Cochlear, Goodman Group, and Macquarie Group. The Motley Fool Australia has recommended Cochlear, Goodman Group, and Macquarie Group. The Motley Fool has a disclosure policy. This article contains general investment advice only (under AFSL 400691). Authorised by Scott Phillips.

More on How to invest

Buy and sell on yellow paper with pins on them and several share price lines.
How to invest

2 ASX 200 shares I'd buy and 2 I'd avoid amid a surging Aussie dollar

The stronger Australian dollar could help some ASX shares while holding others back.

Read more »

Person writing notes with a piggy bank, calculator, and an ascending pile of coins on the table.
How to invest

How I'd use ASX shares to build a second source of wealth

Regular investing can add up to something substantial over time.

Read more »

Happy elderly couple enjoying each other's company.
Superannuation

How to build your superannuation the Warren Buffett way

Superannuation gives investors decades to put patience and compounding to work.

Read more »

Legendary share market investing expert and owner of Berkshire Hathaway, Warren Buffett.
How to invest

5 things Warren Buffett looks for before buying ASX shares

Buffett-style investing means avoiding bad businesses and overpaying for quality.

Read more »

A happy couple relax in a hammock together as they think about enjoying life with a passive income stream.
Dividend Investing

Want income for life? Here's how I'd build an ASX dividend portfolio

Don't chase the highest yields, but build multiple income streams that endure.

Read more »

A man rests his chin in his hands, pondering what is the answer?
Exchange-Traded Funds (ETFs)

Top 3 ASX ETFs for a first-time investor in 2026

Three low-cost funds to start your investing journey.

Read more »

posh and rich billionaire couple
How to invest

How to turn $10,000 into $100,000 with ASX shares

You don't need a spectacular investment idea for compounding to make a big difference.

Read more »

Happy woman working on a laptop.
Blue Chip Shares

3 ASX 200 shares I'd buy for the next decade

Wesfarmers, Goodman Group and CSL: three decade-long ASX holdings.

Read more »