Missouri treats a diminished value claim in Missouri as an ordinary part of property damage. If another driver wrecked your car, courts here let you ask for the repair bill and for the value the car still lost.
Rook and the Before and After Test
The leading case is Rook v. John F. Oliver Trucking, from 1977. The court allowed the cost of repairs plus the difference between the car's market value before the collision and its value after the repairs. It sits in the Matthiesen, Wickert & Lehrer 50-state survey with the other Missouri rulings.
That test tells you what proof to gather. You need a fair price for the car just before the crash and a fair price once the shop was done. A diminished value appraisal supplies both numbers, and a demand letter sends them to the adjuster.
Two Rulings on Your Own Policy
Here the answer depends on the words in your contract. In Lupo v. Shelter Mutual, from 2002, the court held that clear policy language can rule out lost value as a covered loss. An older case points the other way on the facts. In Williams v. Farm Bureau, from 1957, repairs that fell short of restoring function, appearance and value left the insurer owing more.
Read the physical damage part of your policy before you file. If it promises only to repair, the claim belongs with the other driver.
Shared Fault Only Shrinks the Award
Missouri uses pure comparative fault. The Justia survey notes that the state Supreme Court requires courts to apply that doctrine. Your award drops by your share of the blame, however large it is, but you keep the rest.
Five Years and the Money Limits
You have a long window. Section 516.120 gives five years for an action for injuring goods or chattels, which includes a car.
According to the Missouri Department of Revenue, the minimum liability coverage is $25,000 per accident for property. A crash with a newer car can use up much of that on repairs alone.
Small claims court hears money cases of $5,000 or less. The Missouri small claims handbook says it was set up so people can handle those cases themselves, without a lawyer. If an insurer stalls, file through the Missouri Department of Commerce and Insurance.