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Understanding Your Personal Rate of Return

Knowing your personal rate of return can help you determine if you're on track to meet your investment goals

Morningstar.co.uk Editors 12 July, 2013 | 7:00AM

Your fund says it finished the year up 15%. The Morningstar Fund Analyst Report says the same. Yet you only made 10% on the fund for the year.

The fact is, returns depend a lot on how you calculate them. Your actual investment or personal rate of return in a fund may be better—or worse—than you think. Knowing your portfolio's actual returns can help you determine if you're on track to meet your investment goals, and whether your funds are living up to your expectations.

Reported Returns Versus Personal Rates of Return

The simplest way to calculate return numbers—and the way Morningstar and most other sources do it—is to assume you made a single lump-sum investment at the beginning of the reporting period. So the 15% return on your fund assumes that you bought all of your shares right at the beginning of the year.

Often, however, your personal rate of return will be different. If you bought or sold shares during the period for which a return is being calculated, or if you didn't buy exactly at the period's start, your personal return won't match the formulaic return. Put another way: Your fund's trailing 12-month return doesn't tell you how you've been doing if you invested £100 each month rather than £1,200 up front.

Calculating Your Personal Return

Even though personal rates of return are crucial numbers for any investor trying to reach a goal, few fund families provide these returns on investors' account statements. Why not? Many fund companies brush off any suggestions for improved disclosure by arguing that providing more information would only confuse investors, or by pointing to surveys showing that shareholders are satisfied with the status quo.

Until things change, you're on your own when it comes to calculating your personal rate of return. If you choose to enter a portfolio in our Portfolio Manager, you can determine your personal gain or loss in individual funds (and in your entire portfolio) since you made an investment.

How To Do It

Here's what you need to calculate personal returns for a single year:

1. Your ending balance from the preceding year (for a single fund or for a portfolio of funds). For the sake of our example, let's say the preceding year's balance is £2,500.

2. Your ending balance from the year for which you're calculating the returns. In our example, we'll use a final balance of £5,250.

3. How much you invested during the year and the months in which you made the investments. In our example, the investments were £1,000 in May and £1,500 in November.

Note that the beginning balance and the investments during the year are negative numbers when you're using a financial calculator or spreadsheet. That's because you're trying to figure out the internal return represented by the difference between the £5,250 you ended up with and the £5,000 you invested (£2,500 beginning balance plus two investments during the year of £1,000 and £1,500).

If you're using a financial calculator, here's what to do:

1. Make a chart of your monthly cash flows. For a portfolio, pool together the cash flows for all of your funds. Assume that all investments during a month are made at the beginning of that month. Sum your initial balance and any January investment for the first month's entry. Also, determine the value of your fund at the end of the holding period. Locate the cash-flow function on your financial calculator and clear the memory of any old data.

2. As your calculator prompts you, enter cash flows. (Inflows are negative and outflows are positive.) Enter zero for months with no cash flows and enter your ending balance as the final, positive cash flow.

3. Choose the IRR (internal rate of return—another term for personal rate of return) function on your calculator and compute. The result is your monthly personal rate of return.

4. (i) Divide your monthly IRR by 100. (ii) Add 1. (iii) Raise the number to the 12th power (two months in a year). (iv) Subtract 1. (v) Multiply by 100 to get the annual percentage.

See this illustration for how to calculate IRR with a financial calculator.

With a spreadsheet program such as Excel, enter the months and cash flows as shown in this example. Select the IRR function, and you’ll get the monthly personal rate of return for your portfolio. Follow step four above to calculate the Annual IRR.

What Personal Returns Tell You
Calculating your personal rate of return may not be your top choice for filling your free time on a Saturday afternoon. But doing so not only tells you how you're progressing towards your goals, but it also sheds some light on how well you've been investing.

If your personal returns are significantly lower than those listed in other sources or those reported by the fund company, take a close look at when you've been buying and selling. Maybe you bought hot funds after they had already hit the top, or sold when a fund was bottoming out and therefore missed a subsequent rebound. In that case, a disciplined pound-cost-averaging programme could keep you from sabotaging your results. You'll likely find that making short-term swaps in and out of the market—or between different funds—has hurt you more than it has helped.

The information contained within is for educational and informational purposes ONLY. It is not intended nor should it be considered an invitation or inducement to buy or sell a security or securities noted within nor should it be viewed as a communication intended to persuade or incite you to buy or sell security or securities noted within. Any commentary provided is the opinion of the author and should not be considered a personalised recommendation. The information contained within should not be a person's sole basis for making an investment decision. Please contact your financial professional before making an investment decision.

About Author

Morningstar.co.uk Editors  analyse and report on shares, funds, market developments and good investing practice for individual investors and their advisers in the UK.

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