Register For Our Mailing List

Register to receive our free weekly newsletter including editorials.

Home / 122

Learning when to buy and sell shares

At a recent talk I gave at the Australian Investors Association’s National Conference, I received one question more than any other: “Is it time to buy BHP?” Obstreperous commentators - paid by commissions on activity rather than returns – are incentivised to make headlines calling the bottom of the resource slump.

Price contains no information about value

Highly leveraged commodity producers with negative free cash flows, like America’s largest coal producer Alpha Coal, have filed for Chapter 11 bankruptcy protection, amid a steel oversupply emanating from China, and slumping commodity prices. This is the shot-across-the-bow for Vale and Fortescue, and places a darkening cloud above the prospects and future returns for BHP and Rio because highly leveraged producers must produce even more of the commodity amid declining prices to meet their interest expenses.

But these arguments are in fact superficial. At the core of the question is a lack of understanding of the difference between price and intrinsic value. Value is not presented simply because a share price has fallen. Price information is free and the reason it is free is because it contains no information about value.

Predicting share prices, which is in essence what the resource commentators are trying to do, is impossible to do consistently well, at least in the short-term.

Intrinsic value is the vessel that helps navigate the sometimes tempestuous changes in share prices. If you have formed your view on the intrinsic value of a company, you can navigate clearly through the thunder and high seas, the gloom and the hype.

Your share portfolio may still be buffeted around by the twin tides of fashion and sentiment, but with each rise and fall you are able to strengthen it, buying more below intrinsic value and perhaps selling when share prices are well above.

Suppose you have your eye on a company and its shares fall from $15 to $12. Should you buy now? What if you buy at $12 and the shares fall to $10? Suppose you decide to buy more. What if they then decline even further to $8 or even $6? When exactly do you buy?

Only if you are confident that the business is actually worth $15 per share are you able to see a fall in the share price – from $12 to $6, for example – for what it is: a terrific opportunity. The right response is to buy more. If you’re like me and you like chocolate, then surely it is rational to order more when your favourite block is on ‘special’ at the supermarket? It’s the same with shares.

Shares are like groceries

Treat buying shares the same way you buy groceries. You actually want the share price to go down so that you can buy more. Share price declines, particularly those that are produced when everyone around you sees only doom and gloom ahead, are precisely what you want.

But how do you know the shares are cheap? Without the beacon of intrinsic value, how do you know whether to buy more or to panic? Many investors don’t know the value of their shares. They frequently panic when shares fall, and also suffer from the consequences of paying too much.

I have often asked an audience of investors the following question, ‘If the shares of (insert your favourite company) were trading at half price today, would you buy them?’ The response is both rapid and enthusiastic, ‘Yes!’ And yet, sometime later, when the share price does indeed fall 50%, only a small handful of the original group ever buy the shares. Why is that? It is because share prices only fall 50% when there is bad news, either about the company being considered or about the economy or market more generally. And unfortunately, such news often perverts good ideas to bad ones. What was seen initially as a brilliant opportunity becomes a high risk ‘play’ that should be avoided until there is more certainty (and a higher price of course).

Your mother probably told you that first impressions are usually correct. She may not have been talking about shares on sale, but she was right again. What is good advice for choosing friends is also good for selecting shares.

The challenge is knowing when to buy

The easier part of investing is knowing what to buy. For example, is it really so difficult to see that CSL is a better business than Slater & Gordon? Is it that challenging to see that an investor should favour the fund manager Platinum Asset Management over Qantas?

The challenging part of investing isn’t identifying good businesses that you would like to own. The challenging part is knowing when to buy, while the prices of all these companies are gyrating amid noise and influences that may or may not ever impact their businesses.

Nobody should miss out on buying shares in great businesses because of the fear that the shares will go down even more. And there is no need to panic and sell at depressed prices either. But such rational behaviour requires you to have something other than the price to look at. You need to know the value of the business and its shares.

Of course in order to value a company’s shares, one needs to be aware of and have appraised the prospects for the business and its products or services. When the price of iron ore was $140 per tonne, we challenged the notion that the long run average would bear any resemblance to the then recent prices. Indeed at $140, we thought $40 per tonne was more likely to eventuate. We now believe the prospects for Australia and the resource sector are likely to worsen and so we arrive at valuations for resource companies that are much lower than current prices.

 

Roger Montgomery is the Founder and Chief Investment Officer at The Montgomery Fund, and author of the bestseller ‘Value.able’. This article is for general educational purposes and does not consider the specific needs of any investor.

 

  •   14 August 2015
  • 4
  •      
  •   
4 Comments
Jerome Lander
August 13, 2015

Valuation is an imprecise art. A range of values might well be more meaningful than a single point estimate.

Interestingly enough, most fund managers that double down on stocks that are falling tend to do badly over the long term according to my research. Reason being that while they might think they know the value of the business, they may well be mistaken. By doubling down they may take significant risk of throwing good capital after bad and losing large amounts on individual positions; what is infamously known as chasing losers. Remember ultimately all prices go down on their way to zero! "Quality" businesses are increasingly at risk from disruption, obsolescence etc, often by factors that are missed or easily misunderstood by analysts. Quality changes over time and is not a static concept.

Graeme
August 13, 2015

Can't agree with Roger on this one. If I buy a tin of XYZ brand baked beans now for $3, next year for $2 or in a couple of years time for $4 there's a pretty good chance I'll be getting exactly the same product. Thanks to Jerome's disruption and obsolesence etc factors, there's a high probability that the shares current earnings will have changed and prospective earnings changed even more. It may have the same ASX code, but that's about it.

Alex
August 14, 2015

Depends on what your philosophy for investing is. If you are a yield investor like I am, Roger is completely on the ball with this. My whole philosophy of investing is based around this concept, build up a strong core portfolio and add to it when the market heads down. It's the best time to buy, not much good if you're just speculating, but if you are adding to a proven stock, you will do well. If you've held a stock long term, you should have a pretty good idea of what its intrinsic value is to you, and when to add to it. I've followed this philosophy for 30 years, and its worked really well. The GFC presented one of the greatest bargain sales that we'll ever see!

Dean Tipping
August 21, 2015

Well said Alex...if you could buy a Rolls Royce for the price of a Commodore you'd buy 10 of them!!

 

Leave a Comment:

RELATED ARTICLES

Adapting to buying shares when markets fall

Estimating a share’s intrinsic value 101

Feel the fear and buy anyway

banner

Most viewed in recent weeks

Building a lazy ETF portfolio in 2026

What are the best ways to build a simple portfolio from scratch? I’ve addressed this issue before but think it’s worth revisiting given markets and the world have since changed, throwing up new challenges and things to consider.

Get set for a bumpy 2026

At this time last year, I forecast that 2025 would likely be a positive year given strong economic prospects and disinflation. The outlook for this year is less clear cut and here is what investors should do.

Meg on SMSFs: First glimpse of revised Division 296 tax

Treasury has released draft legislation for a new version of the controversial $3 million super tax. It's a significant improvement on the original proposal but there are some stings in the tail.

Ray Dalio on 2025’s real story, Trump, and what’s next

The renowned investor says 2025’s real story wasn’t AI or US stocks but the shift away from American assets and a collapse in the value of money. And he outlines how to best position portfolios for what’s ahead.

10 fearless forecasts for 2026

The predictions include dividends will outstrip growth as a source of Australian equity returns, US market performance will be underwhelming, while US government bonds will beat gold.

13 million spare bedrooms: Rethinking Australia’s housing shortfall

We don’t have a housing shortage; we have housing misallocation. This explores why so many bedrooms go unused, what’s been tried before, and five things to unlock housing capacity – no new building required.

Latest Updates

3 ways to fix Australia’s affordability crisis

Our cost-of-living pressures go beyond the RBA: surging house prices, excessive migration, and expanding government programs, including the NDIS, are fuelling inflation, demanding bold, structural solutions.

Superannuation

The Division 296 tax is still a quasi-wealth tax

The latest draft legislation may be an improvement but it still has the whiff of a wealth tax about it. The question remains whether a golden opportunity for simpler and fairer super tax reform has been missed.

Superannuation

Is it really ‘your’ super fund?

Your super isn’t a bank account you own; it’s a trust you merely benefit from. So why would the Division 296 tax you personally on assets, income and gains you legally don’t own?

Shares

Inflation is the biggest destroyer of wealth

Inflation consistently undermines wealth, even in low-inflation environments. Whether or not it returns to target, investors must protect portfolios from its compounding impact on future living standards.

Shares

Picking the next sector winner

Global equity markets have experienced stellar returns in 2024 and 2025 led, in large part, by the boom in AI. Which sector could be the next star in global markets? This names three future winners.

Infrastructure

What investors should expect when investing in infrastructure: yield

The case for listed infrastructure is built on stable earnings and cash flows, which have sustained 4% dividend yields across cycles and supported consistent, inflation-linked long-term returns.

Investment strategies

Valuing AI: Extreme bubble, new golden era, or both

The US stock market sits in prolonged bubble territory, driven by AI enthusiasm. History suggests eventual mean reversion, reminding investors to weigh potential risks against current market optimism.

Sponsors

Alliances

© 2026 Morningstar, Inc. All rights reserved.

Disclaimer
The data, research and opinions provided here are for information purposes; are not an offer to buy or sell a security; and are not warranted to be correct, complete or accurate. Morningstar, its affiliates, and third-party content providers are not responsible for any investment decisions, damages or losses resulting from, or related to, the data and analyses or their use. To the extent any content is general advice, it has been prepared for clients of Morningstar Australasia Pty Ltd (ABN: 95 090 665 544, AFSL: 240892), without reference to your financial objectives, situation or needs. For more information refer to our Financial Services Guide. You should consider the advice in light of these matters and if applicable, the relevant Product Disclosure Statement before making any decision to invest. Past performance does not necessarily indicate a financial product’s future performance. To obtain advice tailored to your situation, contact a professional financial adviser. Articles are current as at date of publication.
This website contains information and opinions provided by third parties. Inclusion of this information does not necessarily represent Morningstar’s positions, strategies or opinions and should not be considered an endorsement by Morningstar.