The Coinsurance Trap
Rio Grande Fabrication LLC insures a Las Cruces plant under a commercial property form with a 90% coinsurance clause. The building's replacement cost is $2,000,000 and the policy limit carried is $1,440,000. Contents replacement cost is $500,000 with a limit of $450,000. The deductible is $10,000 per occurrence. Business income coverage is written on a 12-month basis with a 72-hour waiting period; the annual business income figure is $180,000. A fire destroys $300,000 of building and $200,000 of stock and machinery. The period of restoration is five months. The insured never requested an agreed-value endorsement and declined the biennial appraisal the agent recommended.
1. Calculate the building payment. Show the coinsurance fraction and explain what the insured bought with its premium savings.
Read the worked answer
Step 1 - Required limit. 90% × $2,000,000 = $1,800,000
Step 2 - Coinsurance fraction. Limit carried ÷ required limit = $1,440,000 ÷ $1,800,000 = 0.80
Step 3 - Apply to the loss. $300,000 × 0.80 = $240,000
Step 4 - Deductible. $240,000 − $10,000 = $230,000 paid
The policy limit of $1,440,000 is not reached, so the fraction - not the limit - drives the reduction.
What the shortfall cost. Had the building limit been $1,800,000, the insured would have collected $290,000 after the deductible. The $60,000 difference is the coinsurance penalty, and the insured is effectively a coinsurer for the uncovered portion of every loss. The insured saved premium on the difference between $1,440,000 and $1,800,000 and gave up far more than it saved on this single fire. Note that the penalty is recalculated at every loss, so a second fire repeats the hit.
2. Calculate the contents payment and the business income payment, and state the total recovery.
Read the worked answer
Contents. Required = 90% × $500,000 = $450,000; carried = $450,000. Fraction = 1.00, so no penalty on this part of the risk. $200,000 of damage is paid in full before the deductible.
Deductible applies once per occurrence. Building $240,000 + contents $200,000 = $440,000 − $10,000 = $430,000 for direct damage. Do not deduct twice; one occurrence, one deductible.
Business income.
- Monthly income figure: $180,000 ÷ 12 = $15,000
- Period of restoration: 5 months → $75,000, plus any continuing expenses and extra expense the form allows
- Waiting period: 72 hours ≈ 3 days × $500/day = about $1,500 not paid
- BI payable: approximately $73,500
Total recovery ≈ $503,500 plus extra expense, subject to the BI limit.
Check the BI limit separately. Business income carries its own coinsurance or agreed-amount provision and is not tested by the property coinsurance fraction. Confirm that the BI limit was set at the annual figure (or higher if the form requires a coinsurance percentage on BI). A second penalty hiding in the BI limit is a common second error.
3. The insured blames the agent. What should the agent have documented, and what placement changes would eliminate this exposure at renewal?
Read the worked answer
Documentation. The agent's defense rests on showing it recommended an accurate valuation and an agreed-value option and was refused. That means a dated record of: the replacement-cost estimate, the recommendation to insure the building to $1,800,000, the offer of the agreed-value endorsement, the biennial appraisal recommendation, and the insured's written declination. A note saying "discussed values" is worth little two years later.
Placement fixes at renewal.
- Raise the building limit to at least $1,800,000 - the coinsurance requirement, not the loan value or the purchase price.
- Agreed-value endorsement - suspends the coinsurance penalty for the scheduled property if the value is accurate at inception. It does not protect against a value that has grown since the endorsement, so re-appraise.
- Blanket rather than specific limits where several locations exist, so an overinsured building can absorb a limit shortfall elsewhere.
- Confirm the BI limit and any extended period of indemnity; five months of restoration is short for a fabrication plant - a rebuild could easily run twelve, and the extra months would be uninsured.
Frame it for the client as risk transfer, not paperwork: the coinsurance clause is a penalty for underinsuring, and the only defenses are accurate values or an agreed-value endorsement.