Unit trust is an easy means of obtaining a spread of investment. It is suitable for passive investor, who doesn’t want to, or doesn’t have extra time to invest their cash savings. For an investment capital to grow, we must not underestimate the power of compound interest – what Einstein calls the “8th wonder of the world.”

Question from a reader

This is a question from a regular reader:

Does compounding interest really apply in unit trust? if so, can you show me how does it apply? If possible, please include how to forecast an investment in unit trust. For example, if I invest RM10,000 today in equity fund, what will i get in 20 years time? Thank you

In fact, the answer can be “yes”, and also “no”. It depends on how you apply the power of compounding interest. If you know how to apply it, unit trust really shows you the power of compounding effect. If you are not mentally prepared, the power of compounding interest is just a myth.

What is the power of compounding interest?

Let’s look at the definition of compound interest:

Interest that accrues when earnings for a specific period are added to principal; thus interest for the following period is computed on the principal plus accumulated interest.

It means you don’t withdraw the interest earned from you capital. Just let the return stay in your investment account and let it compounds. Your next interest return will be calculated using the accrued principal plus interest.

For example, you save RM1,000 in a Fixed Deposit account giving you 4% interest return per annum. Provided that you don’t withdraw any sen from the account, your account balance will look like this:

After 10 years untouched, you will have a total of RM1480.24 in your FD account. If you keep the money there for another 10 years, it not only earns you another interest of RM480.24, but a total of RM1,191. Leave it there for 50 years, you will get a magnificent total of RM7,107.

Use this compound interest calculator to verify the figures.

Notice the curve line growth which is exponential. The most interest earned is at the last few years. The exponential growth will be more significant towards the end.

How to “employ” compound interest?

Imagine you have a loyal employee called “compound interest”. He will work for you day and night non-stop. All you have to do is not to disturb him at work. Let him concentrate to do his job for you. At the end, he will definitely deliver the magnificent results for your hard earned money.

In order to enjoy the power of compound interest, make sure you provide the perfect working environment:
1. Start saving and investing as soon as possible
2. Let your savings and investment accrued and compound as long as possible
3. Try to get the best investment return with bearable risk

Photo by orangeacid

How to apply compound interest in unit trust investment?

No matter where you put your money, provided the money is still yours, compound interest will work for you. Consider the following places where you save your money

  • under your pillow – compound interest still works, but with 0% interest rate.
  • in saving account – compound within 1-2%
  • in fixed deposit account – compound 3.7% p.a.
  • in unit trust – compound with a wider range, say -5% to 20%
  • in shares – compound with an even wider range, say -50% to 100%
  • in properties – hard to predict. If you buy a house that’s never completed, you lost your capital plus interest charges of your mortgage. However, some experienced property investors can get their money compounded many fold per annum.

But if you spend the money instead, I guarantee that compound interest won’t work for you anymore, because the money is no longer yours.

You can even use borrowed money to invest. For instance, you get a home loan to buy house, or borrow money from your parents to invest in stocks. If you manage to get a higher return than the interest charges, compound interest is working for you.

But if you borrow money to spend, compound interest is working against you. The harder it works, the poorer you are.

In order to let compound interest works its wonder in unit trust investment, you should:

1. Never repurchase your fund unit – let your capital stays in there as long as possible. When you want to lock the gain from time to time, use switching facility.
2. Review your portfolio performance regularly – make sure it is giving you positive return as often as possible
3. Invest as early as possible – start investing when you are still young. It will give you the longer term to invest and get through all the equity roller coaster ride when you reap the return at the end.
4. Invest as much as possible
5. Never get tempted to spend your earning – just leave your return in the fund. Forget about it! Leave it until you reach your financial freedom.

How much can you get from RM10,000 initial investment after 20 years?

Use the compound interest formula to calculates the value of a compound interest investment after ‘n’ interest periods.

FV = PV( 1 + i )n


‘FV’ = Future value after ‘n’ interest periods.
‘PV’ = Present value of Principal, the amount invested at the start.
‘i’ = the interest rate applying to each period.
‘n’ = the number of interest periods (number of years for per annum computation)

From the reader’s question above,”If possible, please include how to forecast an investment in unit trust. For example, if I invest RM10,000 today in equity fund, what will i get in 20 years time?“. In this case,

PV = RM10,000
n = 20 years
i = whatever annualized return you think your equity fund can produce

Use this compound interest calculator,

When i = 10%
FV= RM67,275

When i = 15%
FV = RM163,665

When i = 25% (Hey, this is better than Warren Buffett’s portfolio, the world’s best investor)
FV = RM867,362

In fact, it depends on how your investment portfolio is doing for the long term. Sometimes an equity fund can give you 40% return in a year. Sometimes it makes a loss of 30% in extreme bear market. If your portfolio can produce 15% return per annum consistently, that’s already marvelous.

To get decent return from unit trust investment, you can refer my articles about:
The secret of unit trust investment
Asset allocation
Portfolio Rebalancing

Summary for Action

Through the power of compounding, a small amount of money over time can grow into a substantial sum. Investments can increase in value over time – and the longer the time frame, the greater the value. This is achieved through returns that are earned, but not spent. When the return is reinvested, you earn a return on the return and a return on that return and so on. Therefore in order to benefit from the power of compounding returns, you must invest as much as possible, in a lump sum now! And keep on investing or saving whenever you got spare cash. Just don’t spend it!


Personal finance author and trainer

    39 replies to "Does Compound Interest Really Apply to Unit Trust Investment?"

    • Zack

      Beside the compounding effect, ones should also aware of negative compounding.. Unit Trusts usually not giving the positive return consistently every year, hence previous year gain might potentially wiped out or at worst will jeopardizing the capital if the fund keep given the -ve return year by year. This is not impossible and the fact that there are quite numbers of funds that given -ve return for five years streak. Thus ones should implement an active managed portfolio to always make-sure that their investment portfolio is always on track.

    • Lance

      Hi sir, I have a question to ask, does compounding interest really apply also in variable unit link investment? Thanks.

    • Lynn

      hi KC,

      my investment is more to equity, and after 1 year plus…I am now seeing my ‘profit’ to >20%….some is >10% only…should I do switching? I am not really sure how this thing works…:( If I invested with EPF $, I can still do switching at RM25 per switch (as long as I maintain 1000 units in the first fund right?)…then later when the equity price is low again, I switch back? Or should I just leave it there, no need to worry, and adfter 3 or more years, only sell? will my return be as good or better?

    • Vince

      Hi KC Lau,
      I’ve found your blog recently and found out that your tips is really simple and practical.
      Regarding to the compound interest of mutual fund, I have some question:
      1. Isn’t it the profit of mutual fund is depend on the NAV value of purchase time and selling time? i.e. profit = (NAV x unit sold)-(NAV x unit purchase) – agent fees

      2.Does it make a different that if I purchase RM1000 in fund A with NAV=1.0,
      sell it after one year with NAV=1.3 or sell it after 10 years with NAV=1.3? Is the final amount of cash I would get will be different? How is the compound interest work in that case?

      • KCLau

        1. that’s right.

        2. normally unit trust fund will have distribution, where unit NAV is driven down a bit but the number of unit you hold will increase. Compound interest is just a concept that you don’t cash out the gains and let it roll in your investment account for even more profits.

    • Adrian

      Hi ,

      When i look at the Quartely fund review , if show the return of the fund yearly say
      2000 0% 2001 19.09% 2002 13.15%
      if i invest 1k during year 2000 meaning that i will get 19.09% return ?
      how does the compound interest apply into this ?
      can you show an illustration ?

      • KCLau

        Hi Adrian,

        First, the fund report shows the return in a fixed period of time. Normally return showed in 2000 refer to the value difference between 01/01/2000 and 31/12/2000.
        But the price fluctuate every single working day in the whole year. So it depends on when you buy and sell.

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    • Jimy Wong

      thanks for the advices

    • Jimy Wong

      Hi KC Lau,
      Pardon me is i ask too much questions and sometimes you may not in position to answer it.

      • KCLau

        Hi Jimy,

        I can’t say that it is wise to buy new fund every time. However, it might be wise to buy new funds every time because of the lower service charge promotional offer. It all depends on your investment strategy and philosophy.

    • Jimy Wong

      yeah…keep it up all the way u be

    • bigtime

      thanks kc for the info,without a doubt one of the best site i have ever visited in 2008.
      keep it up kc.

      • KCLau

        Thanks for the compliment. I will continue to provide more useful info.

    • Jimy Wong

      would it be wise to buy new fund everytime it launched?

    • Jimy Wong

      Hi KC

      Would be the best to invest lump at offer period and regularly invest to get compound interest?

      Get more units and compound interest?

      • KCLau

        When new fund is launched, normally fund house gives bonus unit ( last time), now is lower service charges.
        Just invest as soon as possible according to your portfolio of choice.

    • Jimy Wong

      Which is better to get better returns?
      1. Invest in lump sum to buy new fund for lower sales charges and get more units at offer period?
      2. Invest regularly into 1 or 2 funds to get compound interest?

      • KCLau

        Hi Jimy,
        There is no absolute answer for this. Compound interest just apply to anything, anywhere that has a value. Invest lump sum will give the best return if you buy at bottom.
        But if the market is at the peak, invest regularly (I mean separate your lump sum into a few times investment at certain period interval) will give you more return than lump sum.
        Again, it is back to the issue of timing. But we will never get the right timing all the time.

        My opinion is, get all your money invested now, in the portfolio of your choice (combination of funds, shares, properties, cash). And invest regularly when you have extra saving in the future.

        Conclusion: just invest all your money larr.. ( even thought putting it in FD is also an investment)


    • rey

      After I have join a course on Quarterly Fund Review Course, now then I know how the compounding interest applies to Unit Trust.

      What I understand is, the compounding interest is actually derives from the capital gain for a certain period.

      If you have a financial calculator, it might be easy to figure out how to get the compounding interest

      Please correct me if I’m wrong

      • KCLau

        I am glad that you understand how compounding interest work.
        It is just a concept that when we don’t withdraw the interest earned, it will add up into the capital and make your next interest earning bigger. When this goes on for a long period of time, the interest earned at later years is very remarkable, even bigger than your initial capital.
        So no matter where you put your money, as long as you don’t withdraw the interest earning, compounding interest effect will work!

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    • rey

      let me do some research on this first 🙂 maybe if i have any new opinion, i’ll post my comment here.

    • rey

      at last, this is wat i really want! thank you KC LAU 🙂

      • KCLau

        Hope it answer your question well, Rey.

    • Relax

      one of the nicest post on compounding that I have ever read.

      • KCLau

        Thanks Relax, you got a lot of time to compound your earning. What a wonderful world for you!

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