The coinsurance clause is the reason a fully covered loss can still be paid short.

Most boards read the property section of a master policy looking for one number, the limit, and treat it as the ceiling on what the policy will pay. The coinsurance clause is the condition sitting underneath that number. It requires the association to insure its buildings to a stated percentage of full replacement cost, commonly 80, 90, or 100 percent, and it measures compliance at the moment of loss rather than at the moment the policy was bought. Fall short of the percentage and the carrier does not simply pay up to the limit. It reduces the payment on the claim in proportion to how far short the limit fell.

An agreed amount endorsement is the switch that turns that condition off. The carrier and the association agree in advance, normally on the strength of a signed statement of values or a current appraisal, that the limit on the policy is accepted as satisfying the coinsurance requirement. For the term of that policy no coinsurance calculation is performed and no penalty is applied. The limit becomes what the board assumed it was in the first place: the ceiling, with no arithmetic underneath it.

The penalty lands on partial losses, which is why it surprises people

The arithmetic is a ratio: what the association carried, divided by what it was required to carry. Take four buildings with a combined replacement cost of 10,000,000 dollars under a 90 percent coinsurance clause. The required limit is 9,000,000 dollars. If the schedule still reflects values set several renewals ago and the policy carries 6,000,000 dollars, the ratio is two thirds. A 900,000 dollar fire, nowhere near the limit, is settled at roughly 600,000 dollars before the deductible. The remaining 300,000 dollars is not a coverage exclusion and not a limit problem. It is the penalty, and it falls to reserves or a special assessment.

This is precisely why the clause escapes notice for years. A board that has never had a large claim has never seen the ratio run, and a board that has only had a total loss may never see it either, because a total loss exhausts the limit anyway and the shortfall shows up as an inadequate limit rather than as a penalty. The exposure lives in the ordinary middle: the kitchen fire, the burst riser, the hail claim that takes three roofs and not the fourth. Those are the losses an association actually has, and they are the ones a coinsurance clause quietly discounts.

Construction-cost inflation is what moves an association from compliant to penalised without anyone deciding anything. Replacement cost is a moving figure, and the required limit moves with it every year. A statement of values filed once and rolled forward unchanged is a limit standing still against a requirement that is not. The association does not fall out of compliance through a decision; it does so through the absence of one.

Why a lender cares whether the endorsement is on the policy

For a condominium the clause is not only a claims question, it is a warrantability question. Fannie Mae and Freddie Mac both expect a warrantable project to carry property coverage on a replacement-cost basis with no coinsurance clause. A master policy written to a percentage floor with coinsurance attached can satisfy a state statutory minimum and still fail that lender review, and when it does the consequence is not a coverage dispute at some future loss. It is a unit sale that cannot close, because the buyer's conforming loan depends on the project being warrantable. This is the same gap measured across every state in our analysis of state insurance minimums against lender requirements, where 40 of 51 jurisdictions set a floor below what the agencies expect.

The agreed amount endorsement is frequently how that condition gets satisfied in practice. Rather than argue about whether a percentage-based limit is adequate, the endorsement removes the coinsurance clause from the policy for the term, which is what the lender is looking for. Boards facing a stalled sale for this reason should read it alongside the wider set of fixes in making a condo warrantable again, since a coinsurance clause rarely turns out to be the only condition a non-warrantable project is failing.

One practical caution: agreed amount is generally granted for the term against the values submitted for that term, and carriers commonly want a refreshed statement of values to continue it. It is not a permanent feature of the program. An association that files identical values for several years running may find the endorsement withdrawn at a renewal, or continued against a limit that has drifted well below current rebuilding cost, which restores the exposure the endorsement was bought to remove. Confirm each year that the endorsement is still attached and that the values behind it are current, rather than assuming both carried forward. The same discipline applies to how those limits are structured across buildings, which is the separate question of blanket versus scheduled limits.