CO 103 denial code

Claim adjustment reason code 103. Often reported as CO 103.

Discount the provider offered

Unofficial reference. This is our own plain-English explanation, not the official code text. Payer rules differ. Verify with the payer and the official X12 code list. AlphaPrefix is not affiliated with X12, CMS or any payer. Data last updated Nov 11, 2026.

What 103 means

The payment reflects a discount the provider offered, such as a senior citizen discount.

The provider gave the patient a discount, and the payer accounts for it on the claim. Senior discounts and similar promotional reductions are typical examples.

Payers may treat discounts differently, and some plans or government programs have rules about routine discounts. If a discount appears that you did not intend, check your billing setup.

Group codes seen with 103

On a remittance, 103 comes after a group code. These are the ones it is most often reported with:

• CO 103 (Contractual Obligation): The provider's side of the ledger. The reduction comes from the payer contract or a rule the provider has to follow, and the patient normally cannot be billed for it.

The payer chooses the group code for each adjustment, so the same reason code can appear with another group code on your remittance. Read the two together. More about group codes.

Common causes

• The practice offers a senior citizen or similar discount and reported it on the claim.
• The billing system applied a promotional discount automatically.
• The payer recorded a discount based on information in the claim.

What to do next

1. Confirm the discount was intended and matches your posted discount policy.
2. Check the payer's and any program's rules on offering discounts to its members.
3. Remove automatic discounts from claims for payers where they should not apply.

Related codes

• 45 (reason code) Charge exceeds the allowed amount