General Liability Class Code
A general liability class code is a five-digit numerical code published by ISO (Insurance Services Office) that categorizes a business according to its operations, products, and services for the purpose of rating and underwriting commercial general liability (CGL) insurance. Each class code carries a base rate that reflects the historical loss experience and expected liability exposure for businesses of that type. The class code is one of the primary inputs that determines a commercial GL premium.
Why GL Class Codes Matter for Independent Agents
Class code selection directly determines the base premium for a CGL policy. An agent who selects the wrong class code can produce a quote that is significantly too high — losing the account to a competitor — or too low, which triggers a premium audit adjustment that surprises the client with a bill months later. Either outcome damages the client relationship.
Beyond pricing, the class code signals the type of risk to the underwriter. Carriers build their appetite around specific class codes. A carrier that writes restaurants aggressively may decline HVAC contractors. When an agent submits a risk with the wrong class code, the underwriter may decline it based on misidentified operations, or worse, issue a quote based on incorrect assumptions about the business. If a claim arises from operations that don't match the coded classification, coverage disputes can follow.
For agents writing small commercial and mid-market accounts, knowing the most common GL class codes for their target industries saves time and reduces errors. Rather than searching through ISO's classification manual for every submission, experienced agents build familiarity with the codes they use most frequently.
How GL Class Codes Work
ISO maintains a Commercial Lines Manual (CLM) that contains thousands of GL class codes organized by industry group. Each class code entry specifies:
- Classification description — What type of business the code covers
- Rating basis — The exposure measure used (gross sales, payroll, area, number of units, etc.)
- Base rate — The premium charge per unit of exposure (e.g., per $1,000 of sales)
- Hazard group — A grouping that reflects relative risk level (I through III, with III being highest hazard)
Common GL Class Code Examples
| Class Code | Description | Rating Basis | Typical Hazard |
|---|---|---|---|
| 10100 | Apartments — building or premises | Area (sq ft) | Low |
| 11126 | Barber or beauty shops | Gross sales | Low |
| 16900 | Contractors — electrical | Payroll | Moderate |
| 16910 | Contractors — plumbing | Payroll | Moderate |
| 18200 | Contractors — HVAC | Payroll | Moderate |
| 45190 | Restaurants | Gross sales | Moderate |
| 41650 | Retail stores — general | Gross sales | Low |
| 91580 | Consulting firms | Gross sales | Low |
Rating Basis Matters
The rating basis determines how the exposure is measured. For a retail store coded to 41650, the premium is calculated based on gross sales — more sales means more customer foot traffic, more products liability exposure, and higher premium. For a plumbing contractor coded to 16910, the premium is based on payroll — more payroll means more field employees performing work that could cause bodily injury or property damage.
The formula is straightforward:
GL Premium = (Exposure / $1,000) x Base Rate x Experience Modifier x Schedule Credits/Debits
For example, a restaurant (class code 45190) with $1.2 million in gross sales and a base rate of $1.85 per $1,000 of sales would calculate as:
($1,200,000 / $1,000) x $1.85 = $2,220 base premium before modifiers
Schedule credits and debits then adjust the premium up or down based on individual risk characteristics.
GL Class Codes vs. Workers' Comp Class Codes
Agents sometimes confuse GL class codes with NCCI workers' compensation class codes. While both classify businesses by operation, they serve different lines of coverage and use different coding systems:
| Feature | GL Class Codes | Workers' Comp Class Codes |
|---|---|---|
| Publisher | ISO | NCCI (or state bureau) |
| Format | Five digits | Four digits |
| Purpose | CGL rating | Workers' comp rating |
| Rating basis | Varies (sales, payroll, area) | Always payroll |
| Example | 16900 (Electrical contractor) | 5190 (Electrical wiring) |
A single business often has different codes for GL and workers' comp. An electrical contractor might be classified under ISO code 16900 for GL and NCCI code 5190 for workers' comp. Agents must verify both codes independently.
Connection to Commercial Insurance Quoting
Accurate class code assignment at the quoting stage prevents downstream problems. When entering a risk into a comparative rater or carrier portal, the class code is typically one of the first fields required. Selecting the wrong code changes the premium, sometimes dramatically — a consulting firm mistakenly coded as a general contractor could see a quote three to five times higher than it should be.
When remarketing a renewal, agents should verify that all carriers are using the same class code for the risk. Different carriers may interpret a business's operations differently, especially for businesses that span multiple classification categories. A company that manufactures and installs products, for example, might be coded under manufacturing by one carrier and contracting by another, producing widely different premiums that are not truly comparable until the classification is reconciled.
Frequently Asked Questions
How does an agent determine the correct GL class code?
Start with ISO's Commercial Lines Manual, which provides classification descriptions and "cross-reference" entries that point related operations to the correct code. The key is identifying the insured's primary operations — the activity that generates the most revenue or represents the core business purpose. When a business has multiple operations, the classification rules determine whether to assign a single code for the dominant operation or split the exposure across multiple codes.
What happens if the wrong class code is used?
If the class code understates the risk, the carrier may issue an audit adjustment after the policy term, billing the insured for the additional premium owed. If the class code overstates the risk, the client overpays and may lose confidence in the agent. In extreme cases, a carrier may deny a claim if the actual operations differ materially from the coded classification and the carrier can demonstrate it would not have written the risk as presented.
Do all carriers use ISO class codes?
Most admitted carriers use ISO class codes as their foundation, but some modify the classification system with proprietary codes or sub-classifications. Carriers like biBERK, NEXT Insurance, and Hiscox may use simplified classification schemes for their small commercial platforms. Agents should verify the class code mapping when moving an account between carriers.
Can a business have more than one GL class code?
Yes. If a business has distinct operations that fall into different classifications — for example, a company that operates both a retail store and a contracting division — the agent may need to assign separate class codes with separate exposures for each operation. ISO's classification rules specify when operations should be combined under one code versus separated.