What Is The Difference Between Stacked And Unstacked Car Insurance? 
The stacked / unstacked option refers to uninsured motorist bodily injury coverage on your auto insurance policy . This option is only offered in a handful of states , most states do n't have this option . stacking applies to policyholders who have more than one vehicle on their auto insurance policy . If you choose the stacking option , it multiplies your amount of uninsured motorist bodily injury coverage -LRB- UM -RRB- by the number of vehicles that you have on the policy . for example : if you have UM coverage of $ 100,000 / $ 300,000 , and you own 3 vehicles and select the stacking option , you now have $ 300,000 / $ 900,000 in UM coverage . 