NovTwo funding currencies should not disappear into one average rate
A property purchase may be funded from more than one currency. Keep the remaining conversion visible instead of hiding it inside a blended historical average.
This article reflects the named expert’s practical perspective. See NovAsia’s editorial policy for how material is prepared and reviewed.
Half the purchase may already be sitting in dollars while the rest remains in euros. Blending both into one average exchange rate makes the spreadsheet tidier and the next decision harder to see.
An average can be useful for historical accounting. It can describe the overall currency cost of a completed purchase or help the buyer review what happened over time. The difficulty begins when that backward-looking number is used to answer a forward-looking question.
Assume a $100,000 property purchase. The buyer already holds $50,000 and needs to fund the remaining $50,000 from euros. The dollar half no longer requires a conversion today. The euro half does. A blended rate across the whole transaction can make the remaining exposure look smaller than it really is.
I would rather show each source of funds on its own line. How much of the obligation is already covered in the settlement currency? How much still needs to be converted? Which currency will fund that gap, and when? Those questions may look less sophisticated than an average-rate formula, but they are more useful for the next payment.
Historical purchase rates are another reason averages can mislead. The existing dollars may have been bought months or years ago. The euros may come from current income. A weighted average combines prices from different periods and different decisions. That can be perfectly legitimate for personal accounting while still being irrelevant to today’s conversion choice.
There is a psychological effect too. If the earlier dollars were acquired at a very favourable rate, the blended figure can make an expensive new conversion look harmless because the average still appears good. The current transaction has not become cheaper; the old gain is simply masking it. The reverse can happen when an unfavourable historical purchase drags down the average even though today’s remaining conversion is attractive.
The same logic becomes more important with instalments. A buyer may have dollars available for the next payment, euros earmarked for a later one, and future income expected to fund the final balance. The useful model is not one average rate for the property. It is a funding map that shows which obligations are already covered and which still depend on future events.
Keeping currencies separate also preserves information about liquidity. Two buyers can end up with the same average exchange cost and very different financial positions. One may have converted almost all available cash into the settlement currency. The other may have converted only what is needed soon and kept a large reserve in the original currency. The average does not capture that difference.
If there are three funding currencies, the answer is not to build an even more elaborate blended number. The first task is still to identify the uncovered portion of the settlement obligation. Then each source can be evaluated by the amount it needs to contribute and the conditions under which that contribution will be converted.
Once the purchase is complete, the buyer can absolutely calculate a blended rate if that helps with record-keeping or performance analysis. At that point the average answers a historical question: what was the effective currency cost across the full sequence of conversions? It should not be confused with the cost of the next unexecuted step.
This distinction also reduces unnecessary arguments about whether an old exchange was “good” or “bad”. That decision is already in the past. The buyer now needs to know what remains to be funded and what choices are still open. Historical averages can inform the record without controlling the next action.
A useful metric earns its place by answering the decision in front of the buyer. An average exchange rate can describe the past. The next property payment usually needs a more direct number: the amount still missing in the settlement currency and the current cost of funding that gap.