Combined Single Limit (CSL)
Also known as: CSL
Example: $1M CSL pays up to $1M total across BI and PD. Compares with split limits like '$100K/$300K/$100K' which has separate per-person, per-accident, and PD limits. CSL is more flexible and the standard commercial auto choice.
Real-world scenario
Riverside Bloom Florists, a six-van delivery shop in Sacramento, renews its commercial auto policy and chooses a $1,000,000 Combined Single Limit instead of a cheaper split limit of $100,000/$300,000/$50,000. The CSL upgrade raises the annual premium from $8,400 to $9,600 across the fleet, with a deductible of $1,000 per collision. Owner Dana figures the extra $1,200 a year is cheap protection against one bad intersection.
Eight months later, a Riverside van runs a red light and strikes a car carrying two passengers. The driver suffers $420,000 in medical bills and $180,000 in lost wages; the passenger's injuries add $260,000. Property damage to the other car totals $38,000, and the plaintiff's attorney demands $150,000 more for pain and suffering. The single blended demand reaches $1,048,000.
Because the CSL pools bodily injury and property damage into one per-occurrence limit, the full $1,000,000 is available to any combination of those claims — unlike a split limit that would have capped bodily injury per person at $100,000 and left Riverside exposed. The insurer pays the $1,000,000 limit plus $65,000 in defense costs (this policy defends outside the limit). Riverside's stacked umbrella then absorbs the remaining $48,000, and Dana pays only her $1,000 deductible. The $1,200 premium difference prevented a six-figure out-of-pocket judgment.
How it affects your premium
Carriers price a Combined Single Limit higher than an equivalent-looking split limit because a single pooled bucket is easier for a claimant to fully exhaust. The main drivers of a CSL premium include:
- Limit selected — moving from a $500,000 to a $1,000,000 CSL typically adds 15-30% to the auto premium because the full amount is available to any one claim.
- Vehicle type and weight — heavy trucks and delivery vans carry more severe-injury potential than a sedan, raising the CSL rate per unit.
- Radius and use — long-haul or urban delivery routes expose the pooled limit to higher-severity crashes than local, low-mileage driving.
- Driver records (MVRs) — violations and at-fault history on pulled motor vehicle reports push the CSL premium up sharply.
- Defense-cost treatment — whether defense is paid inside or outside the limit (see defense inside vs. outside limits) changes both price and how much of the CSL survives a lawsuit.
- Umbrella attachment — a required underlying CSL to support an umbrella can dictate a $1,000,000 floor, raising the primary auto cost.
- Loss history — prior at-fault claims and open reserves lift the rate at renewal.
Common misconceptions
Myth: A $1,000,000 Combined Single Limit is the same as a $1,000,000 split limit.
Reality: They are very different. A split limit caps bodily injury per person, bodily injury per accident, and property damage separately, so no single injury can access the whole amount — while a CSL lets one claim draw on the entire pooled limit.
Myth: The Combined Single Limit refreshes for every claim during the year with no ceiling.
Reality: The CSL is a per-occurrence figure. Commercial auto liability usually restores the full limit for each separate accident with no annual cap, but when a CSL sits on a liability policy that also carries an aggregate limit, total payouts for the policy period are still capped — so heavy claim frequency can exhaust coverage.
Myth: With a CSL I don't need an umbrella.
Reality: A single serious multi-victim crash can exceed $1,000,000; an umbrella sits above the CSL to catch the excess judgment and defense costs.
Frequently asked questions
What does Combined Single Limit actually mean?
Is a CSL better than a split limit for my business?
Does the Combined Single Limit include defense costs?
What CSL limit do I need to attach an umbrella?
Can a Combined Single Limit be exhausted by one accident?
Sources cited
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