What happens if a comic book is slabbed and then later downgraded?

If a comic book is downgraded after being slabbed, the grading company will typically issue a refund for the slab fee. The downgraded comic will be returned to the seller or the buyer, depending on the terms of the sale. The grading company’s grading standards are very strict, and downgrades are rare. However, factors like significant damage or deterioration can lead to a lower grade.