Home Bias Calculator NZ 2026/27
Almost every investor in every country holds too much of their own market, and New Zealanders hold the most extreme version of it, because the home market here is unusually small relative to the concentration people carry. A New Zealand investor with 30 percent of their portfolio in domestic shares is not tilting slightly towards home; they are holding hundreds of times what a globally weighted portfolio would hold. The percentage difference does not convey this, which is part of why the bias persists. Thirty points sounds like a preference. Six hundred times sounds like what it is. This page measures your position against the global benchmark and reports it as a multiple as well as a difference, treats Australia separately from New Zealand because so many local funds report the two as one category and thereby hide how small the domestic slice is, and then adds the part almost nobody counts. For most New Zealanders the family home is the largest asset by a wide margin, and it is entirely exposed to one small economy, one currency and one property market, alongside a job and a superannuation scheme tied to the same place. Including it usually changes the picture more than any decision about the share portfolio would. None of this argues that home bias is an error. There are real arguments for some of it, including imputation credits and the absence of currency risk, and this page lays them out. The question is whether the amount you hold is the amount you decided to hold.
Benchmark weight is user-entered from a global index factsheet. The rest of the world benchmark is calculated as 100% less the two you enter.
Multiple = your weight / benchmark weight. This is the honest framing when the benchmark is a fraction of a percent, because a percentage-point difference understates the concentration badly at that scale.
Dollars overweight = portfolio value × (your weight − benchmark weight). A negative figure means you hold less than a global weighting would.
Including home equity adds the equity in your home to both the New Zealand-linked total and the overall total. Equity means the value less the mortgage, since the mortgage is not your asset.
KiwiSaver belongs in the portfolio figure. It is where most unrecognised New Zealand exposure sits, particularly in conservative and balanced funds, and leaving it out understates the result substantially.
Excluded: your income and future earnings, which are also New Zealand-linked for most people; New Zealand Superannuation entitlements; business ownership; and the currency exposure embedded in unhedged foreign holdings.
No provider is named, ranked or recommended, and this page does not state a correct allocation.
Not financial advice. Last verified: .
Your portfolio against the global benchmark
| Region | You hold | Benchmark | Multiple | Your dollars | Difference |
|---|---|---|---|---|---|
| New Zealand | 30.00% | 0.05% | 600x | $30,000.00 | $29,950.00 |
| Australia | 10.00% | 1.50% | 6.67x | $10,000.00 | $8,500.00 |
| Rest of the world | 60.00% | 98.45% | 0.61x | $60,000.00 | -$38,450.00 |
| Total | 100.00% | 100.00% | 1x | $100,000.00 | $0.00 |
The multiple column is the honest one. At a benchmark of a fraction of a percent, a percentage-point difference badly understates the concentration.
Once your home is counted
| Asset | Value | NZ-linked | Share of total |
|---|---|---|---|
| Portfolio, New Zealand share | $30,000.00 | $30,000.00 | 8.57% |
| Portfolio, everything else | $70,000.00 | $0.00 | 20.00% |
| Equity in your home | $250,000.00 | $250,000.00 | 71.43% |
| Total | $350,000.00 | $280,000.00 | 100.00% |
| Exposed to New Zealand | $280,000.00 | 80.00% |
Your income is tied to the same economy and is not counted here, so this remains an understatement rather than an overstatement.
What each allocation looks like as a multiple
| If your NZ weight were | Multiple of benchmark | Dollars in NZ | Overweight by | Reading |
|---|---|---|---|---|
| 1.00% | 20.0x | $1,000.00 | $950.00 | Close to a global weighting |
| 5.00% | 100x | $5,000.00 | $4,950.00 | A deliberate modest tilt |
| 10.00% | 200x | $10,000.00 | $9,950.00 | A substantial tilt |
| 20.00% | 400x | $20,000.00 | $19,950.00 | Heavily concentrated |
| 30.00% | 600x | $30,000.00 | $29,950.00 | Heavily concentrated |
There is no correct row here. The point is to see which one you are on, since most people have never worked it out.
Percentage Points Hide The Scale
A 30% allocation against a 0.05% benchmark is a difference of 29.95 percentage points, which sounds like a preference. It is 600x the global weighting, which is what it actually is.
That gap between how the two framings feel is most of the reason home bias persists. Nobody would deliberately choose six hundred times a benchmark weight, and plenty of people are comfortable with thirty percent.
Worked Example: $100,000 With 30% In New Zealand
$30,000.00 in New Zealand shares and bonds, against the $50.00 a globally weighted portfolio would hold at a 0.05% benchmark. Overweight by $29,950.00.
$10,000.00 in Australian shares against a $1,500.00 benchmark weighting, overweight by $8,500.00 and 6.67x the benchmark. Australia is a genuinely larger market, so the same dollar tilt is a far smaller multiple.
The rest of the world gets $60,000.00 against $98,450.00, so it is underweight by $38,450.00 and held at 0.61x the global weighting.
Australasia Is Not One Market
Many New Zealand funds report a single Australasian allocation, which is where a lot of this hides. Combining the two makes the domestic slice invisible.
On the worked example the pair together are 40.00% against a combined 1.55% benchmark, which is 25.8x. Split apart, New Zealand alone is 600x and Australia is 6.67x.
Splitting them is the single most useful thing you can do with a factsheet, because it moves the New Zealand figure from a number that looks reasonable to one that demands a decision.
Then There Is The House
For most New Zealanders the portfolio is not the largest asset, and the home bias question is not really about shares at all.
Adding $250,000.00 of home equity to a $100,000.00 portfolio produces $350,000.00 of assets of which $280,000.00, or 80.00%, is tied to New Zealand.
That figure still understates it, because your income is tied to the same economy, your future New Zealand Superannuation entitlement is tied to the same government, and if you own a business it is almost certainly tied to the same customers.
The risk this creates is not that any one asset is bad. It is that they all move together. A difficult decade for New Zealand affects the job market, house prices and the portfolio at the same time, and that correlation is invisible when each is looked at on its own.
The Arguments For Some Of It
Home bias is a choice rather than an error, and three arguments for it are genuine.
Imputation credits. New Zealand companies attach credits for tax already paid, which reduces the tax a New Zealand investor pays on the dividend. Foreign shares carry no equivalent.
No currency risk. A domestic holding is worth what it is worth. An unhedged foreign holding moves with the exchange rate as well as the market, and our currency hedged vs unhedged calculator shows how large that effect is.
Simpler tax. Foreign shares held outside a PIE can bring the foreign investment fund rules into play once the threshold is crossed. Our FIF de minimis calculator covers where that line sits.
Those justify some home bias. Whether they justify hundreds of times the global weight is a different question, and the honest answer is that they justify a tilt rather than a concentration.
Fixing It Without Selling Anything
The cheapest correction is to direct new money rather than move old money, which avoids both transaction costs and any tax event on realised gains.
Check the KiwiSaver allocation first, because that is where most of the unrecognised exposure sits and switching within a scheme is usually free. Conservative and balanced funds carry large domestic weights and most members have never looked.
Our fund overlap calculator shows the combined position across everything you hold, and our portfolio rebalance calculator works out the amounts to move.
Related NZ Portfolio Calculators
- Fund Overlap Calculator: your combined allocation across every fund.
- One Fund vs Multi-Fund Calculator: what control over the weights costs.
- Currency Hedged vs Unhedged Calculator: the currency risk on foreign holdings.
- FIF De Minimis Calculator: where the foreign investment fund threshold sits.
- Portfolio Rebalance Calculator: the amounts to move.
Related calculators
- Imputation Credit Gross-Up Calculator: NZ Dividends.
- Index Concentration Calculator NZ 2026/27: how concentrated an index fund really is.
- Index Fund Projection Calculator NZ: long-Term Investment Growth.
- Investing Through A Company Calculator NZ 2026/27: investment income through a company against a PIE, following the imput.
How to measure home bias in a New Zealand portfolio
- Add up what sits in New Zealand. Include New Zealand shares held directly, the New Zealand portion of every fund you hold, and your KiwiSaver's New Zealand allocation. KiwiSaver is where most of it hides, because conservative and balanced funds carry large domestic weights.
- Treat Australia separately. Many New Zealand funds hold Australasian shares as a single category. Australia is a genuinely larger market than New Zealand, so combining them hides how small the domestic slice really is.
- Get the benchmark weights from a factsheet. Any global index fund publishes a country breakdown. Use the current figures rather than the defaults here, because weights drift and the defaults are indicative only.
- Read the multiple, not the difference. A gap of thirty percentage points sounds moderate. Expressed as a multiple of the benchmark weight it is not, and the multiple is the honest framing when the benchmark is a fraction of a percent.
- Add your house. For most New Zealanders the home is the largest asset and it is entirely exposed to one small economy. Including it changes the picture more than any portfolio decision does.
- Decide what you are being paid for the concentration. Home bias is a choice, not an error, and there are arguments for some of it. The question is whether the amount you hold is the amount you decided to hold.