13.2 The Coinsurance Formula & Underinsurance Penalties

13.2 The Coinsurance Formula & Underinsurance Penalties

Key Focus: In commercial property underwriting, over 90% of all reported losses are partial rather than total. If commercial enterprises were permitted to insure only 20% or 30% of their property's value to protect against minor fires and water losses, insurers would collect inadequate premium pools while carrying catastrophic exposure. The Coinsurance Clause solves this moral and actuarial problem by penalizing insureds who fail to maintain an agreed percentage (typically 80%, 90%, or 100%) of true insurable value at the time of loss.

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The Economic Rationale of Coinsurance

Property insurance rating is built on the fundamental assumption that policyholders will insure their assets to full or near-full value. When an insurer establishes a rate (e.g., $0.40 per $100 of insured value), that rate assumes the full pool of capital is at risk.

If Business A and Business B each own an identical $1,000,000 commercial building, but:

• Business A purchases an $800,000 policy limit and pays an annual premium of $3,200;
• Business B purchases a $200,000 policy limit and pays an annual premium of only $800.

If both buildings sustain an identical $100,000 partial kitchen fire, and both received full payment of $100,000, Business B would receive an unjust windfall while contributing only one-quarter of the premium necessary to support the loss pool. The coinsurance clause rectifies this inequity by turning underinsured policyholders into co-insurers, forcing them to bear a mathematical proportion of their own partial losses.

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The Coinsurance Formula Anatomy

When a loss occurs to commercial property subject to a coinsurance condition, the adjuster calculates recovery using the standard statutory formula:

$\text{Payment} = \left( \frac{\text{Did}}{\text{Should}} \right) \times \text{Loss}$

Where:

• Did: The actual limit of insurance purchased and carried by the policyholder on the damaged asset class;
• Should: The minimum dollar limit of insurance the policyholder ought to have maintained at the date of the loss: $\text{Should} = \text{Actual Value of Property at Time of Loss} \times \text{Coinsurance \%}$
• Loss: The actual, covered physical damage sustained by the property;
• Property Value: Assessed strictly on the policy's settlement basis (Actual Cash Value if written on an ACV form; full Replacement Cost if the policy contains a Replacement Cost endorsement).

                                  ┌────────────────────────────────────────────────────────┐
                                  │             THE COINSURANCE FORMULA STEPS              │
                                  └───────────────────────────┬────────────────────────────┘
                                                              │
                     ┌────────────────────────────────────────┼────────────────────────────────────────┐
                     ▼                                        ▼                                        ▼
     ┌───────────────────────────────┐        ┌───────────────────────────────┐        ┌───────────────────────────────┐
     │    STEP 1: CALCULATE SHOULD   │        │     STEP 2: DETERMINE RATIO   │        │    STEP 3: MULTIPLY & DEDUCT  │
     ├───────────────────────────────┤        ├───────────────────────────────┤        ├───────────────────────────────┤
     │ Property Value at Loss        │        │ Divide 'Did' (Limit carried)  │        │ Multiply Ratio by Gross Loss. │
     │ MULTIPLIED BY                 │   ──>  │ BY                            │   ──>  │ Then SUBTRACT Policy Deductible│
     │ Coinsurance % (80% or 90%)    │        │ 'Should' (Required Limit)     │        │ Result = Net Indemnity        │
     │ = 'Should'                    │        │ (Cap Ratio at 1.00 / 100%)    │        │ (Subject to Max Limit 'Did')  │
     └───────────────────────────────┘        └───────────────────────────────┘        └───────────────────────────────┘

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Five Cardinal Rules of Coinsurance Adjustment

Every RIBO Level 1 candidate must master the five universal rules governing coinsurance claims adjustment:

Rule 1: The Policy Limit Is an Absolute Ceiling

The insurer will never pay more than the limit of insurance carried (Did), regardless of the formula calculation, the size of the loss, or the degree of overinsurance.

Rule 2: The Principle of Indemnity Prevents Profit

The insurer will never pay more than the actual cash value or replacement cost of the loss suffered, even if the formula produces a theoretical number exceeding the loss.

Rule 3: Ratio Capped at 1.00 (100%)

If the insured carried more insurance than required (Did > Should), the ratio is capped at 1.00. The policyholder does not receive a bonus or windfall payout for being overinsured; the loss is simply paid in full (subject to deductible and policy limit).

Rule 4: Total Losses Bypass the Coinsurance Penalty

Coinsurance applies strictly to partial losses. In a total catastrophic destruction where the loss equals or exceeds the property's value or the policy limit, the coinsurance formula does not reduce the payout. The insurer pays the full face limit of the policy (Did). Coinsurance exists to prevent underinsuring for partial claims, not to withhold contracted policy limits during a complete burn-down.

Rule 5: Deductibles Apply After the Coinsurance Calculation

In commercial property claims involving both a coinsurance penalty and a deductible, standard claims adjustment in Ontario calculates the penalty on the gross loss first, and then applies the deductible to the resulting figure: $\text{Net Settlement} = \left[ \left( \frac{\text{Did}}{\text{Should}} \right) \times \text{Loss} \right] - \text{Deductible}$ (Note: If the loss exceeds the policy limit by an amount greater than the deductible, the deductible is absorbed by the uninsured excess, and the full face limit is paid).

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The Two Percent Waiver of Coinsurance Clause

A standard feature in Canadian commercial property forms is the Two Percent (2%) Waiver Clause (often called the De Minimis waiver). Conducted properly, determining whether an insured has met their coinsurance percentage requires an expensive, formal certified appraisal of the entire building, machinery inventory, and stock on the exact day of the loss.

To avoid crippling adjustment expenses on minor claims, the policy stipulates:

"The Coinsurance Clause does not apply to any loss or damage where the total loss does not exceed 2% of the total limit of insurance on the property involved, or $10,000, whichever is the lesser dollar amount."

Operational Test for the 2% Waiver

1. Calculate 2% of the insurance limit carried (Did): $\text{Limit} \times 0.02$
2. Compare this figure against the fixed benchmark of $10,000;
3. The lesser of these two figures becomes the waiver ceiling;
4. If the gross property loss is less than this ceiling, the coinsurance clause is completely waived! The loss is adjusted in full (less deductible) without any inquiry into the property's true value.

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Step-by-Step Worked Mathematical Scenarios

Case 1: Full Compliance (Did >= Should)

• Premises: Commercial retail building in Mississauga.
• Building Value at Loss: $1,500,000.
• Coinsurance Clause: 80%.
• Limit Carried (Did): $1,200,000.
• Partial Fire Loss: $150,000. Deductible: $2,500.

Calculation Steps:

1. $\text{Should} = $1,500,000 \times 80% = $1,200,000$.
2. $\text{Ratio} = \frac{\text{Did}}{\text{Should}} = \frac{\text{1,200,000}}{\text{1,200,000}} = 1.00$ (100% compliance).
3. $\text{Payment} = (1.00 \times $150,000) - $2,500 = $147,500$.

• Outcome: The insured met the coinsurance requirement and recovers the entire loss minus the deductible.

Case 2: Underinsurance Penalty (Did < Should)

• Premises: Precision metal fabrication facility in Kitchener.
• Equipment Value at Loss: $1,000,000.
• Coinsurance Clause: 80%.
• Limit Carried (Did): $600,000 (severely underinsured).
• Partial Machinery Loss: $160,000. Deductible: $5,000.

Calculation Steps:

1. $\text{Should} = $1,000,000 \times 80% = $800,000$.
2. $\text{Ratio} = \frac{\text{Did}}{\text{Should}} = \frac{\text{600,000}}{\text{800,000}} = 0.75$ (75% ratio).
3. Gross recovery before deductible: $0.75 \times $160,000 = $120,000$.
4. Net payment after deductible: $$120,000 - $5,000 = $115,000$.

• Financial Consequence: The insured suffers a $40,000 coinsurance penalty ($160,000 - $120,000) plus the $5,000 deductible, absorbing a total out-of-pocket deficit of $45,000 due to underinsurance.

Case 3: 90% Coinsurance with Rising Construction Values

• Premises: Commercial office complex in Ottawa.
• Building Value at Loss: $4,000,000 (surged due to inflation from $3,000,000).
• Coinsurance Clause: 90%.
• Limit Carried (Did): $2,700,000.
• Water Escape Loss: $360,000. Deductible: $10,000.

Calculation Steps:

1. $\text{Should} = $4,000,000 \times 90% = $3,600,000$.
2. $\text{Ratio} = \frac{\text{Did}}{\text{Should}} = \frac{\text{2,700,000}}{\text{3,600,000}} = 0.75$ (75% ratio).
3. Gross recovery: $0.75 \times $360,000 = $270,000$.
4. Net payment: $$270,000 - $10,000 = $260,000$.

• Financial Consequence: The insured absorbs a $90,000 underinsurance penalty plus the $10,000 deductible.

Case 4: Total Catastrophic Loss (Coinsurance Inapplicable)

• Premises: Industrial warehouse in Sudbury.
• Building Value at Loss: $2,000,000.
• Coinsurance Clause: 80% ($\text{Should} = $1,600,000$).
• Limit Carried (Did): $1,200,000.
• Total Fire Loss: $2,000,000. Deductible: $5,000.

Calculation Steps:

1. If we incorrectly applied the formula: $\frac{\text{1,200,000}}{\text{1,600,000}} \times $2,000,000 = $1,500,000$.
2. However, under Rule 1, the policy limit (Did) is the absolute ceiling: $$1,200,000$.
3. Furthermore, because this is a total loss, the coinsurance penalty does not operate. Because the actual loss ($2,000,000) exceeds the policy limit ($1,200,000) by $800,000, the $5,000 deductible is absorbed by the uninsured loss.

• Settlement: The insurer pays the full face limit of $1,200,000.

Case 5: The Two Percent (2%) Waiver in Action

• Premises: Commercial strip plaza in Vaughan.
• Building Value at Loss: $3,000,000.
• Coinsurance Clause: 80% ($\text{Should} = $2,400,000$).
• Limit Carried (Did): $1,200,000 (carrying only 50% of the required limit!).
• Windstorm Roof Damage: $8,000. Deductible: $1,000.

Calculation Steps:

1. Calculate 2% of limit: $0.02 \times $1,200,000 = $24,000$.
2. Compare against fixed dollar cap: $$10,000$.
3. The lesser amount is $10,000.
4. Since the actual loss of $8,000 is less than $10,000, the Two Percent Waiver applies.
5. Settlement: $$8,000 - $1,000 = $7,000$.

• Outcome: The insured receives payment without any coinsurance penalty, saving $3,000 that would otherwise have been forfeited under a 50% underinsurance penalty.