AAIS COMMERCIAL UMBRELLA LIABILITY COVERAGE RATING CONSIDERATIONS

(October 2025)

INTRODUCTION

Although there is no single standardized method for calculating commercial umbrella liability premiums, the American Association of Insurance Services (AAIS) offers a recommended rating and pricing approach. However, this approach is neither filed nor mandatory. Multiple methods and techniques can be employed to determine the premium of an umbrella policy. This article reviews the AAIS recommended approach.

AAIS PREMIUM DETERMINATION

Step 1. Develop The Manual Premium For Each Underlying Coverage.

There are two ways to determine the manual premium:

Example: Dino's Delicatessen is in an East Coast tourist town. It operates Monday through Friday, serves breakfast and lunch, and closes at 2:30 p.m. It also occasionally caters to off-site events and delivers sack lunches to businesses that participate in Lunch 'n Learn meetings.

Dino's package policy premium is calculated using standard rates, with only a package credit applied to its property and liability premiums because of its relatively small size.

Dino’s owns two full-size vans, which they use exclusively in the catering and delivery operations. Coverage is written with a surplus lines insurance company due to catering and delivery operations, and the maximum legally permitted scheduled debit factors are applied to the premium rates.

In this case, the umbrella carrier easily determines the underlying premises/operations and products/completed work manual premiums. The manual premise liability premium is $1,250, and the manual product liability premium is $3,000. However, it takes more work and creativity to arrive at a fair estimate of a "manual" auto liability premium.

After conducting a thorough analysis, the umbrella carrier determines a total manual liability premium of $5,000 for the two vehicles.

Step 2. Determine The Catastrophe Potential Factor For Each Underlying Coverage.

This is the first step in calculating the premium. For example, a risk might have a low underlying premises exposure, moderate exposure for products/completed work, but a very high commercial auto exposure. These hazard factors are used during underwriting and influence rating and pricing. Consider these points at this step:

Low Hazard

These exposures are unlikely to exhaust the underlying limits. Typically, offices and small retail exposures fall into this category. Hired and non-owned auto represent a low hazard auto exposure.

Medium Hazard

These exposures involve a moderate risk of experiencing a catastrophic loss. This category often includes multi-location retail stores, restaurants, and casual or artisan contractors. Typical auto exposures in this group are contractors with low-weight vehicles, company sales fleets, and local delivery services.

High Hazard

These exposures are significantly different as they involve the highest risk of catastrophic loss. Examples include manufacturing facilities, large public auditoriums, concert venues, and bridge contractors. Auto exposures such as buses, cement trucks, and taxi fleets are also classified as high-hazard.

Example: Continuing with Dino's, even though the premises/operations and products/completed work exposures are reasonable, the umbrella carrier assigns a grade of low for the premises liability exposures but a medium hazard grade for products because of the possibility of food spoilage. It assigns a medium hazard grade to the auto liability exposure due to its off-premises catering operations and delivery in an urban setting, which often experiences high traffic congestion during lunch-time deliveries.

Step 3. Multiply The Manual Premium For Each Underlying Coverage By The Catastrophe Potential Factor Selected.

The insurance company uses a table of factors based on coverage and hazard grades.

NOTE: Rating a Businessowners policy is more complex because some policies are composite rated. This means the premiums for premises/operations and products/completed work are combined, not distinctly separated from the total premium. Sometimes, this factor applies to the entire Businessowners premium; other times, it may necessitate consulting the insurance company for clarification.

Example: We will keep going with Dino's. This is the preliminary premium calculation up to this point.

Coverage

Manual Premium

Factor / Rate

Premium

Premises And Operations

$1,250

Low / 0.17

$213

Products/Completed Work

$3,000

Medium / 0.20

$600

Commercial Auto Liability

$5,000

Medium / 0.18

$900

Step 4. Total All Premiums Developed In Step 3. This Is The Umbrella/Excess Liability Premium For The First $1,000,000 Limit.

 

Example: Dino's premium for the first $1,000,000 umbrella/excess liability is $1,713. This is based on adding all three premiums from the table above.

Step 5. Multiply Step 4 by the Individual Risk Premium Modification (IRPM) factor. This is the modified premium for the first $1,000,000 limit of liability.

These credits or debits recognize special risk characteristics that the rates do not reflect. The net credit or debit determined under this rule applies to all other rating procedures. The total credit or debit cannot exceed 25%, subject to individual state regulations.

Example: After thoroughly reviewing the application, previous loss experience, and loss control report, the umbrella liability carrier decides not to credit or debit the risk.

Step 6. Apply the Higher Each Occurrence Factor to Step 5. to develop the additional premium charge for limits above $1,000,000.

 

Example: Dino wants umbrella liability quote options for limits of $2,000,000, $3,000,000, $4,000,000, and $5,000,000. This chart outlines how this is done and the premiums for each limit if the limits factor for each layer is .50.

Dino's Higher Umbrella Limits Quotes

Each Occurrence Limit

Premium For

Multiplied By

Premium

Total Premium

$2,000,000

$1,000,000: $1,713

.50

$857

$2,570

$3,000,000

$2,000,000: $857

.50

$429

$2,999

$4,000,000

$3,000,000: $429

.50

$214

$3,213

$5,000,000

$4,000,000: $214

.50

$107

$3,320

NOTE: The premium for each $1,000,000 is subject to a minimum premium per million, as determined by the insurance company.

Example: Dino requests Commercial Umbrella Liability Coverage with a $4,000,000 limit for an annual premium of $3,213.

ALTERNATIVE RATING APPROACHES

As mentioned in the introduction, there is not a single, standardized method or formula for determining commercial umbrella liability premiums. AAIS suggests using the approach outlined above, but it is neither filed nor required. It is important to remember that each insurance company may choose its own or multiple different methods.

Always verify which approach the insurance company is using.

Related Article: ISO Commercial Liability Umbrella Coverage Form Rating Considerations

PREMIUM AUDIT

Commercial umbrella liability coverage forms or policies may or may not be subject to audit. Typically, if the underlying commercial general liability premium is based on an auditable exposure, such as payroll or sales, then the umbrella policy is usually also subject to audit.