In a standard off-plan payment structure, ninety percent of a unit's price can reach the developer before the building is finished. Installments arrive on a schedule, either calendar-based or tied to construction milestones, and by the time a buyer collects a key, most of the capital is already gone. That arrangement is ordinary. What it does to judgment is not. This is the sunk cost trap, and a half-built property portfolio is where it does its quietest damage.
Picture the position most active off-plan buyers eventually hold. Not one unit but several, bought across two or three projects, each at a different stage. One tops out next quarter. One is a slab and a sales gallery. One handed over last year and is renting below the number in the original projection. The portfolio is half-built in the literal sense, and half-built portfolios generate a specific kind of pressure. Every few months another payment comes due, and each payment feels less like a fresh decision than like a defense of the ones already made.
The sunk cost trap, in one rule
Behavioral finance has a clean definition for this. A sunk cost is money already spent that cannot be recovered by any future choice. The rule that follows is equally clean: sunk costs should carry no weight in a forward decision. The only question that matters at any milestone is whether the next dollar, committed today, earns an acceptable return from today's starting point. What came before is a fact about the past. It is a receipt. It is not an argument for what to do next.
The reason this is hard in real estate, and hardest in off-plan, is that the payment schedule is a psychology as much as a cash-flow plan. Money leaves the account in visible increments over years, and each increment deepens the feeling of commitment. By the time the market delivers real information, whether the district softened, whether comparable resale went thin, whether the yield came in below plan, the buyer is already most of the way in. The structure supplies doubt and depth of exposure at exactly the same moment.
The only question worth asking at the next milestone
The disciplined investor runs one test at every payment. Set aside everything already paid. Treat the unit as if it appeared today at its current stage, with its current completion risk, its current rental reality, and its current resale market. Would you commit the remaining installments to acquire it now, on those terms? If the honest answer is yes, keep paying. If the honest answer is no, the remaining payments are not protecting the earlier ones. They are compounding the error.
Most investors cannot run this test cleanly because the earlier payments keep intruding. The mind insists that stopping now wastes what is already in. It does not. The prior capital is spent under every scenario, whether the investor continues or walks. The choice is only ever about the money still under the investor's control.
Escalation, one installment at a time
The trap rarely announces itself. It works through small, reasonable-sounding steps. A milestone payment falls due on a project that has slipped. The investor pays, because the alternative feels like admitting a mistake. The next payment falls due, larger in cumulative terms, and the same logic applies with more force, because there is now more to defend. This is escalation of commitment, and it is how a portfolio that should have been trimmed at thirty percent exposure ends up fully paid at ninety, defended all the way down by the very capital that should have been the signal to stop.
The offset an off-plan buyer accepts at purchase, the foregone rental income and reduced liquidity during construction, was priced as a bet on the finished asset. When the finished asset no longer supports the bet, continuing to pay does not recover the offset. It only adds to the sum at risk.
Read the book, not the position
A half-built portfolio is not one decision. It is a set of independent forward decisions that happen to share an owner. Treating it as a single emotional whole is what keeps weak positions alive. Read it unit by unit. Some should be completed, because the forward return still holds. Some should be held past handover and let, because the yield survives contact with the net numbers after vacancy, management, service charge, and withholding tax. And some should be released, even at a realized loss, because the capital and attention they consume would earn more elsewhere in the same market.
Releasing a position at a loss is the hardest of these, and the one the sunk cost trap most reliably prevents. A realized loss stings because it converts a paper judgment into a closed fact. But the loss was incurred when the market moved, not when the investor acknowledged it. Recognition is not the wound. It is the treatment.
The decision made before the emotion arrives
The defense against this is not willpower at the milestone. It is a rule written before the milestone, when the mind is calm and no payment is due. Before entering an off-plan position, a disciplined buyer sets the conditions under which they would stop: a completion delay beyond a defined point, a resale market below a defined depth, a net yield beneath a defined floor. The triggers go into the file at purchase, alongside the payment schedule, so that the decision to continue or exit is made by the investor's earlier, unemotional self rather than by the version standing at the next payment with capital already committed and pride attached.
This is unglamorous work, and it is the work that separates a portfolio from a collection of hopeful positions. It costs nothing to write the rule in a quiet quarter. It costs a great deal to improvise one in the middle of a soft market with an installment due.
The sunk cost trap does not punish investors for what they paid. It punishes them for letting what they paid decide what they pay next.
The investor who prices each remaining payment on its own forward merit will sometimes complete, sometimes hold, and sometimes walk, and will treat those as three ordinary outcomes rather than as verdicts on character. That discipline is quieter than conviction, and it outlasts it.
At My First Corner, reading a half-built portfolio position by position, and being candid about which units are worth finishing, is the work we do before a client sends the next payment rather than after. The conversation is available when it is useful.
