Stacked insurance combines bodily injury liability limits for your policy’s underinsured and uninsured motorist coverage. If you’re in an accident with an uninsured or underinsured driver, you’ll have a higher coverage limit and need to pay less out of pocket if you stack insurance.
Depending on your situation, you may be able to stack coverage across multiple policies or multiple vehicles on one policy.
Not all states allow drivers to stack insurance coverage. While stacked insurance comes with a higher payout, it’s also typically more expensive than unstacked insurance. Even so, stacked insurance is worth considering, especially if you live in a state with lots of uninsured motorists.
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You can stack multiple bodily injury liability coverage limits. Stacked insurance provides more coverage but is also more expensive.
You might want to consider stacking coverage if you have more than one car insured under the same policy or have your name on more than one auto insurance policy.
If you live somewhere with a high percentage of uninsured drivers, you can benefit from stacked insurance.
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Stacked vs. Unstacked Insurance: What’s The Difference?
Stacked insurance provides more coverage by allowing policyholders to stack coverage limits for the bodily injury liability section of uninsured and underinsured motorist coverage. Stacked insurance is typically more expensive than unstacked insurance.
Also sometimes called non-stacked insurance, unstacked insurance restricts the use of uninsured motorist bodily injury coverage to the bodily injury limits of the vehicle involved. In this case, you wouldn’t be able to combine multiple limits from other cars or policies to increase your coverage. If you have unstacked insurance, your coverage is limited to the specific coverage limit for the vehicle in question.
In the context of car insurance, “stacking” refers to combining the uninsured motorist (UM) coverage limits provided by multiple policies or to multiple insured vehicles. For example, if your UM limit is $25,000 with one policy and $50,000 with another, stacking (or combining) those limits would give you $75K in UM bodily injury coverage.
Stacking increases your coverage depending on how many vehicles you own under one policy and how many policies your name is on. For example, if you own two cars under one policy, you can stack their coverage limits. Similarly, if your name is on multiple policies — such as a spouse or family member’s policy — you may also be able to stack coverage limits for those vehicles.
Two Types of Insurance Stacking
There are two main types of insurance stacking: stacking within one policy and stacking across multiple policies, also known as vertical and horizontal stacking. Some states only allow one type of stacking but not the other, and some states don’t allow stacking at all, so it’s important to explore which options are available to you.
Stacking Across Multiple Policies
Horizontal stacking — also called interpolicy stacking — allows policyholders to stack coverage across multiple vehicles insured under multiple policies. Stacking multiple policies generally only applies to policies under a single company. Filing the same claim with two different insurers to get multiple payouts doesn’t qualify as “stacking” — it’s just insurance fraud.
For example, you might have insurance for your own vehicle with a $35,000 uninsured motorist bodily injury coverage limit. At the same time, your name is also on your parent’s insurance policy, which has $25,000 in uninsured motorist injury coverage. For slightly higher premiums, you can stack these insurance policies for $60,000 in coverage should you get in an accident with an uninsured driver.
Interpolicy'' stacking, also known as horizontal stacking, refers to combining uninsured motorist bodily injury coverage across multiple policies. Your name must be on both insurance policies issued by a single company to qualify for interpolicy stacking.
Stacking Within One Policy
You can also stack coverage vertically, otherwise known as intrapolicy stacking, by combining coverage for multiple vehicles insured under the same policy.
For example, say you own two cars covered under the same auto policy and with $15,000 of UM coverage. If you vertically stack policies, you’ll have $30,000 in combined UM bodily injury coverage.
"Intrapolicy" stacking, also known as vertical stacking, refers to stacking uninsured motorist bodily injury coverage across multiple vehicles under the same policy. If you own multiple vehicles, you may be able to take advantage of vertical stacking.
States That Allow Insurance Stacking
Not all states allow insurance stacking, and some states allow vertical stacking but not horizontal stacking. According to Allstate, 32 states allow at least one form of insurance stacking, while 18 states prohibit it. Twenty-two states allow both forms of stacking, while 10 only allow vertical stacking.
The Types of Stacking Each State Allows
It’s important to keep in mind that even if your state allows stacking coverage, your insurer may not. Some states also have specific limits in place for stacking, so be sure to speak to your provider directly to explore your options for coverage.
Should You Stack Coverage?
Stacking insurance coverage usually means paying higher premiums. Before you decide to stack insurance coverage, evaluate whether or not it’s worth the extra cost.
If you’re only insuring one vehicle, paying for stacked insurance coverage is likely costly. However, if you own multiple vehicles or have your name on multiple policies, stacking insurance coverage could pay off in the event of an accident. If you do get into an accident with an uninsured motorist, you could receive significantly more coverage.
In this instance, stacking uninsured motorist coverage is also relatively inexpensive — in many cases, it could mean you only end up paying a few extra dollars a month.
When deciding whether or not you need to stack insurance coverage, consider the percentage of uninsured drivers in your state. The more uninsured drivers in the area, the more beneficial it is to stack your insurance coverage since it’s more likely that you could be in an accident with someone without insurance. The following table breaks down the percentage of uninsured drivers by state.
Top 5 Least-Insured States
Percentage of Uninsured Drivers
Top 5 Most-Insured States
Percentage of Uninsured Drivers
Mississippi has the highest percentage of uninsured drivers at 29.4%, while New Jersey has the lowest percentage at 3.1%. If you live in an area with many uninsured motorists, then uninsured motorist coverage can help cover the cost if you get into an accident.
If you live in a low-risk state or don’t have multiple vehicles you need to insure, it makes sense to go with unstacked insurance coverage. On the other hand, if you own multiple cars and live in a higher-risk area, stacking your insurance could increase your coverage.
FAQs About Stacked Insurance
Stacked insurance can help protect you in the event of an accident, but it can be a little confusing for drivers not familiar with the topic. We’ll break down some frequently asked questions about stacked insurance.
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- Allstate. "Stacked Vs. Unstacked Car Insurance." Accessed October 21, 2021.