A home you live in is an unusual asset to hold in a portfolio

The largest holding most households own

For a household that owns property, the property is usually worth more than everything else it holds put together. That alone makes it worth examining as an investment rather than only as a place to live, whatever the emotional relationship with it.

It is not, however, an ordinary holding. It is a single indivisible asset in a single location, it cannot be sold in parts, and its value depends heavily on circumstances specific to that street and that town rather than on anything diversified.

None of this is an argument against owning a home. It is an argument for being clear-eyed about what kind of asset it is, particularly when it is described as an investment in conversation as though it were comparable to a diversified holding.

Concentration is unavoidable here in a way it is not elsewhere

Everywhere else in a portfolio, concentration is a choice that can be reduced by spreading money across more holdings. With a home it cannot, because the smallest unit available is an entire property, and the household needs somewhere to live.

That produces a position most people would reject if it were proposed in any other form: a very large proportion of net worth in one asset, in one place, in one market, frequently in the same town where the household earns its income.

The overlap with income is the part worth noticing. A local downturn can affect both the value of the property and the household’s earnings at the same time, which is the same pattern that makes holding investments tied to your own employment uncomfortable.

There is not a great deal to be done about it directly, since living somewhere is not optional and dividing a house is not possible. What can be done is to avoid compounding the concentration elsewhere, by not adding further holdings that depend on the same local conditions.

Borrowed money magnifies the movement in both directions

Property is one of the few things households routinely buy largely with borrowed money, and that changes the arithmetic considerably. A modest movement in the value of the asset produces a much larger movement in the household’s equity, because the debt does not move at all.

Take an illustration. A property bought for 200,000 with 40,000 down carries 160,000 of debt. A 10% rise in value adds 20,000 to a 40,000 stake, which is a 50% gain on the money committed. A 10% fall does exactly the same in reverse.

This is why property is often described as having produced excellent returns and why the experience of it differs so sharply between households. The underlying asset generally moves modestly; the borrowing is what turns a modest movement into a large one.

The transaction costs are unlike anything else

Buying and selling property involves professional fees, taxes or duties in many places, moving costs and a process that takes months rather than seconds. Those costs are substantial enough that they materially change the return over short holding periods.

That is one reason property tends to reward long holding periods: the entry and exit costs have to be recovered before anything else counts. It is also why comparing a few years of house price movement with a few years of some other holding is misleading unless the costs are included.

Ongoing costs belong in the sum too. Maintenance, local charges and the periodic replacement of expensive components are real and continuous, and a return calculated from purchase price to sale price alone quietly omits every one of them.

Against all of that sits the shelter the property provides, which would otherwise have been paid for. Any honest comparison has to include that benefit as well as the costs, which is one reason these arguments are so rarely settled.

A dual-purpose asset resists tidy analysis

The deepest complication is that a home is simultaneously an investment and a consumption good. It provides shelter, which has a value that would otherwise be paid in rent, and it may change in price. Treating it purely as one or the other produces a distorted picture either way.

It also cannot be sold to realise a gain without creating the need to acquire somewhere else, usually in a market that has moved similarly. A rise in the value of a home a household intends to keep living in is, in cash terms, less useful than it sounds.

How any of this should influence a household’s decisions depends entirely on circumstances, on local property taxation and rules, and on what else it holds. Anything involving a property is a decision of size by definition, and it belongs with a regulated adviser rather than with a general account of the mechanics.