Worst · median · best returns: what holding for 3 months, 1, 3 or 5 years has earned in the past

A standard trailing return only tells you what you would have earned if you had bought exactly 1 year ago, but real investors buy on different days. This section answers a question closer to real life: if you had bought on any day in the past and held for the full period, what were the worst, typical and best results?

It is in the "Consistency" section of the fund page, drawn as a box chart, and appears once a fund has at least about 7 months of NAV history. The "Consistency" row in the peer comparison card at the top of the page sums up the 1-year holding results in one line.

Reading the box chart

The box shows the range where half of all outcomes fall. A narrow box means results were similar whichever day you started; a wide box means the timing of your investment mattered a lot. Hover over a column to see how many outcomes it is based on.

How it's calculated

1. Every day with a NAV counts as one starting point, and we look at the return you would have earned by holding for the full period. For example, a fund with 5 years of NAV history has about 2 years of start dates that can complete a 3-year hold, or roughly 480 outcomes
2. Return for each outcome = NAV on the end date ÷ NAV on the start date − 1, using NAV with dividends reinvested. For example, holding for 3 months as the NAV goes from 10.00 to 10.35 baht = +3.50%
3. From 1 year upward, returns are converted to % per year: (1 + total return) ^ (1 ÷ number of years) − 1. For example, holding for 3 years as the NAV goes from 10.00 to 12.10 baht gives 21% in total, or 1.21 ^ (1 ÷ 3) − 1 ≈ 6.56% per year
4. Sort all outcomes from lowest to highest. The first is the worst, the last is the best, and the one in the middle is the median
5. Profitable % of the time = number of outcomes above 0 ÷ total number of outcomes. For example, 423 out of 480 ≈ 88%

Why it helps

• Not tied to the day you look: the 1-year trailing return changes every day, but this view combines every starting point, so it gives a more realistic picture
• Risk you can see in money terms: "worst −21.5%" is easier to understand than a volatility figure
• See how much time helps: many funds that once lost heavily over short holds have a positive worst case over long holds

How to use it

1. Look at the worst case for the period you plan to hold and ask yourself whether you can accept it. If you plan to hold for 1 year and the worst case is −21.5%, be prepared to see your money fall by that much
2. Find the period at which the worst case turns positive. In this example it is 5 years. If your goal is shorter than that, this fund may be too risky for that money
3. Compare medians between funds of the same type over the same period. The median is the typical outcome, not the lucky one
4. Compare box widths. A fund with a narrower box gives more predictable results, which suits people who don't want to bet on timing