Simply put:

If you bought a fund which worth 5000$. And after one month, the value of the fund roses to 5500$. Then you sell it for 5500$. Then your profit will will be 500$ (let's ignore any transaction fees here). Since you only invested 5000$, so the rate of return will be 500/5000, which is 10% for this month. Note this is for one month only.

Usually, people use year as the unit of time. In the above case, your return will be: 10% per month, times 12 months a year, with the assumption that the performance will remain the same over the year. So your return rate is about 10%x12 = 120% (which usually it too good to be true though).

When people talks about return, they usually refers to the above return by year, ignoring any transaction fee or broker fees, tax, etc.

If your funds has dividend, then simply add the dividend rate to the above return, as a rough extimate (I say "rough", since there are a lot other issues). Unless you buy these dividend rich funds, usually, your return is mostly determined by the appreciation of the fund's price (just like a stock).

As a final way to help you understand it, just go to finance.yahoo.com, type in your fund's ticker, then go to its "Performance" on the left, watch for the numbers in the section "TRAILING RETURNS (%) VS. BENCHMARKS", and "ANNUAL TOTAL RETURN (%) HISTORY". These are the numbers you may most be interested in ---- in terms of the "return".

For example, this one: http://finance.yahoo.com/q/pm?s=PRLAX

The above is just my 2 cents, mostly based on general stock based funds.

[此贴子已经被作者于2007-1-13 21:06:07编辑过]