Playbooks / Risk
Concentration limits
The rule
Nobody sets out to be concentrated. Concentration is what happens when a series of individually reasonable decisions accumulate in the same direction.
How it happens
An investor buys an apartment in a building they know. It goes well. They buy a second in the same development, because they now understand the building, the agent and the service charge. The third comes from the same developer because the relationship exists.
Every step was defensible. The result is a portfolio exposed to one developer, one owners association, one micro-market and one chiller plant.
Add that their salary comes from a company in the same city and their savings sit in a currency pegged to the same dollar, and the entire balance sheet needs one set of conditions to hold.
The exposures worth limiting
Single asset. What share of net worth is in one property. For most people the honest answer, including the home, is uncomfortably high.
Single building or development. Two units in one tower share a service charge regime, a reserve fund, a handover glut and a reputation.
Single tenant. Especially for anyone letting to one corporate tenant, where a lease ending and a vacancy are the same event.
Single employer. Salary, and in the Gulf frequently residency, and sometimes shares or a bonus scheme. One employer can be three exposures.
Single currency. Covered in currency risk and the peg, and worth counting here as a line rather than assuming it is handled elsewhere.
Single counterparty. One bank, one broker, one platform.
Setting a limit that survives
The limit has to be written down before the opportunity appears, alongside the rest of your investment policy statement, because the whole point is that the good opportunity is exactly when you will want to breach it.
Pick numbers you can live with rather than numbers that sound rigorous. Something like: no single property above a stated share of net worth, no more than two units in any one building, no more than a stated share of liquid assets with one institution. The precise figures matter far less than having them at all.
Then write down what you will do when a limit binds, because it will. The useful answer is rarely sell something. It is more often stop adding, and let the rest of the balance sheet grow into the gap.
The awkward truth
Most wealth is built through concentration and most wealth is lost the same way. A concentration limit does not maximise expected outcomes, and someone who never set one will always be able to point at somebody who did better without one.
It is insurance against the version of events where the concentrated bet does not work, chosen deliberately, priced in foregone upside. That is a trade worth making consciously, and a trade almost nobody makes by accident.
The arithmetic
Where it breaks
- Limits set as percentages of net worth move as net worth moves, which means a falling market can breach a limit without any decision being taken. Decide in advance whether the limit is checked on the way down as well as up.
- It reduces expected return. Concentration is how most large fortunes were made, and a limit is a deliberate trade of upside for survivability.
- The primary residence distorts every ratio and there is no consensus on whether to include it. Pick a treatment and stay with it rather than switching to whichever answer is more comfortable.
- Illiquid assets cannot be trimmed to a limit. For property the only enforceable version is a limit on what you add, which means the limit has to exist before the purchase.
- Counting exposures separately hides the correlation between them. Salary, residency and local property are one exposure wearing three coats.
- A limit you will breach for a good enough opportunity is not a limit. It is a preference, and it will not be there on the day it is needed.
When to use it
Before the second property in the same building, which is where most concentration begins. Also as a standing annual review, because concentration accumulates without any single decision creating it.
The Safe Withdrawal Rate does this arithmetic for you, in your currency, in about thirty seconds.
Open the calculatorSources
- Bank for International Settlements, property price statistics
- Dubai Land Department, transaction data
Last reviewed . Educational research, not personal advice. Disclosure standards.