- Calculate overlap using underlying holdings and portfolio weights.
- Foreign-asset returns and exchange-rate changes combine multiplicatively.
- A fund’s trading currency does not, by itself, establish currency hedging.
Diversification distributes exposure across investments rather than depending on one outcome. Its usefulness depends on the underlying holdings, how their risks overlap, and the currency in which future spending will occur.
Count exposures, not fund names
Two funds with different names can hold many of the same companies. A broad-market fund plus a technology fund may increase exposure to technology companies already prominent in the broad index.
Consider a hypothetical portfolio split equally between two funds. Company A is 8% of the first fund and 20% of the second. Your combined exposure is 0.50 × 8% + 0.50 × 20% = 14%, not an average level of diversification inferred from owning two funds. These weights are assumptions, not figures from an actual fund.
Inspect holdings, sector weights, geography, and major issuers together. ASIC’s Moneysmart diversification guide explains spreading exposure across asset types and markets. Its examples use Australia, while the underlying concentration questions also apply elsewhere.
Distinguish allocation from diversification
Asset allocation is the division among categories such as stocks, bonds, and cash. Diversification concerns how risk is distributed within and across them. Many stocks can still leave a portfolio dominated by equity risk. Bonds can share issuer, interest-rate, and credit risks even when their names differ.
The appropriate comparison depends on time horizon, required spending, and the ability to withstand losses. Diversification does not prescribe a universal portfolio mix or prevent broad market losses.
Include currency in the return calculation
An overseas asset’s local-market return and its return in your spending currency can differ. Moneysmart identifies exchange-rate changes as a risk for overseas investments in its ETF guide.
Suppose an unhedged investment rises 10% in its foreign currency, while each unit of that foreign currency buys 10% less of your spending currency. Ignoring costs, the combined return is 1.10 × 0.90 − 1 = −1%. A starting value of 1,000 currency units becomes 990. Adding +10% and −10% would incorrectly give zero; the two changes multiply.
This is an illustration, not an exchange-rate forecast. Overseas exposure can reduce dependence on one market while adding currency risk relative to planned spending.
Trading currency is different from hedging
The currency used to buy a fund on an exchange is a quotation and settlement choice. It does not, by itself, change the currencies of the underlying assets. Buying a foreign-asset fund in your own currency therefore does not establish that its currency risk has been hedged.
Check the fund’s actual hedging policy, the share class, and the currency against which exposure is hedged. Vanguard’s explanation of hedged ETFs describes using contracts to offset currency movements. Hedging can also reduce favorable currency effects, involve costs, and leave residual exposure. It does not remove the market risk of the holdings.
Make the comparison testable
Compare portfolios using the same date, spending currency, and valuation basis. Record dominant holdings, sector and country exposure, relevant currencies, any hedging policy, and fees. Then ask which loss scenarios could affect several holdings at once.
A compound-interest calculation assumes a return; it does not measure diversification or forecast currency movements. The knowledge quiz gives you a way to test the underlying reasoning.