How will you know when it's time to take your profit?

What is the secret behind knowing when to sell your ASX shares? Is it all just guesswork? Or is there a science to it? We take a closer look.

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

Way back in 1969, there was a company called Poseidon No Liability – not to be confused with its namesake Poseidon Nickel Limited (ASX: POS), which is the renamed Niagara Mining Limited and currently trades on the ASX.

Back to Poseidon the former. The company was an obscure miner that announced a major discovery of nickel in Western Australia. This commodity was in very short supply and high demand with the Vietnam War raging.

At the time, nickel was selling on the London market for £7,000 a ton (or approximately AU$25,000 converted to today's value).

Some lucky investors had bought Poseidon shares for just 80 cents, but after the company announced its nickel discovery, the shares quickly rose in value and reached $12.30 – more than 15 times higher. But this was just the beginning.

a woman

Absolute fortunes were made, and lost

Without any further statements from Poseidon, the share market caught nickel fever. The Poseidon share price rose further and further and kept on rising until it ultimately reached a share price of $280 in February 1970.

Many clever investors made extraordinary profits – literally millions – by selling as the shares rose. Others bought in and held their investment, losing fortunes as the Poseidon share price crashed back to next to nothing.

So, what is the secret behind knowing when to sell? Is it all just guesswork? Or is there a science to it?

Knowing when to leave

It's first worth reminding ourselves that the economists define 'profit' as 'the reward for risk'. Every investment in the share market has an element of risk attached and there is no scientific or fool-proof answer to optimising profit.

However, realism is one answer. Vigilance offers another.

How much do you realistically believe would constitute a fair and reasonable profit on your investment? Set that figure as your goal and as your shareholding approaches that figure, sell.

It also pays to be aware on at least a daily basis of movements in the price of your shares. Your investment is not a set-and-forget proposition, it requires constant monitoring. When you are totally on top of market movements you can act swiftly to capitalise and gain. 

The one question every investor wants answered

As you've no doubt gathered, there is no solid answer to the question of knowing when to take profits with a sale. Maybe that's why we are all so enthralled with the share market – its ups and downs, its moods and tantrums.

The market seems to rise and fall on the dubious strength of a whispered rumour or the international significance of an impeachment vote. But that is exactly why we love it.

There will always be risks to be taken and profits to be made. Just knowing when to sell is the 64 dollar question.

Motley Fool contributor Gregory Butler has no position in any of the stocks mentioned. The Motley Fool Australia has no position in any of the stocks mentioned. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. 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

A happy couple looking at an iPad feeling great as they watch the Challenger share price rise
How to invest

How to make $50,000 of retirement income with ASX shares

This could be the way to retire with a healthy pay check each year.

Read more »

Happy man holding Australian dollar notes, representing dividends.
Dividend Investing

How to generate $20k of passive income from BHP shares

BHP could provide investors with a big pay check in 2023.

Read more »

A woman looks quizzical as she looks at a graph of the share market.
How to invest

How can I hope to retire rich when the share market is falling?

Dividends can save your retirement if you treat them right.

Read more »

A man walks up three brick pillars to a dollar sign.
How to invest

I'd aim for $1 million, thanks to just a few ASX shares

Here's how I'd go about it.

Read more »

A couple are happy sitting on their yacht.
How to invest

How I would invest in ASX shares to retire rich

I think the share market is the place to be if you want to retire rich.

Read more »

School boy wearing glasses standing in front of chalk board with maths and share price calculations on it
Investing Strategies

Which valuation metrics matter most when picking ASX shares?

There are many ways to measure a company's worth. So how do you choose the best ones when determining which…

Read more »

A formally dressed young woman sips tea from a china cup and saucer as she gives a haughty look against the background of a European style drawing room with heavy wood, traditional wallpaper and a large chandelier hanging from the ceiling.
How to invest

How to become a millionaire with ASX shares

Forget the lottery and take your wealth into your own hands by investing.

Read more »

Young investor watching share chart in anticipation
Cheap Shares

How to spot an ASX share price bargain

Here are three ways you can tell if a share is in the bargain bin.

Read more »