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CO-P26 Denial Code: Adjusted per Voluntary Provider Network

CO-P26 means a property and casualty payer adjusted payment based on a Voluntary Provider Network (VPN), a network the provider joined by agreement. The carrier applied the network's contracted terms instead of paying the full charge or fee schedule amount.

Quick facts

Code
CO-P26 (CARC P26)
Status
Active In use since November 1, 2017.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The only group allowed for P26. The adjustment is contractual, and the claimant isn't billed for it.
Official description
Payment adjusted based on Voluntary Provider network (VPN). Usage: If adjustment is at the Claim Level, the payer must send and the provider should refer to the 835 Class of Contract Code Identification Segment (Loop 2100 Other Claim Related Information REF). If adjustment is at the Line Level, the payer must send and the provider should refer to the 835 Healthcare Policy Identification Segment (loop 2110 Service Payment information REF) if the regulations apply. To be used for Property and Casualty only. (Use only with Group Code CO).
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-P26 means

CARC P26 says payment adjusted based on Voluntary Provider Network (VPN). X12 limits it to property and casualty claims and requires group code CO.

A voluntary network is one the provider elects to join by signing an agreement, usually in exchange for referrals or faster payment from participating P&C carriers. When a carrier pays under that agreement, the reduction from your charge (or from the fee schedule amount, where state rules allow) is reported as CO-P26.

As with other network codes, the usage note points to the contract reference: the 835 class of contract code segment (loop 2100 REF) at claim level, or the healthcare policy identification segment (loop 2110 REF) at line level, when regulations apply.

The distinction from CO-P25 is that a Medical Provider Network may be tied to state rules that direct injured workers’ care, while a voluntary network is purely contractual. The practical steps are similar: confirm the agreement and the rate.

Common causes

  • VPN contract rate applied to the bill.
  • Network rental, where your VPN contract is leased to other carriers.
  • Wrong network matched to your tax ID by a bill review vendor.
  • Terminated agreement still in the carrier’s system.

How to handle it

  1. Identify the network and the contract referenced on the remittance.
  2. Check your agreement, including rates, effective dates, and rental provisions.
  3. Verify the payment against those terms and any state limits.
  4. Post valid adjustments as contractual; don’t bill the claimant.
  5. Dispute invalid discounts with the carrier or network, including proof of termination if applicable.

How to prevent problems

  • Track every voluntary network agreement and its scope.
  • Review rental provisions before signing.
  • Terminate unwanted networks in writing and keep confirmation.
  • Monitor network discounts by carrier on remittances.

Specialty notes

High-volume P&C providers such as PT, chiropractic, and occupational medicine clinics often belong to several networks, and overlapping agreements can produce unexpected CO-P26 discounts.

Remark codes that may appear with CO-P26

  • N381 (Alert: Consult our contractual agreement for restrictions/billing/payment information related to these charges.): Directs you to the contractual agreement that set the rate.
  • N663 (Adjusted based on an agreed amount.): Adjusted based on an agreed amount.
  • CO-P25 (Payment adjusted based on Medical Provider Network (MPN).): Adjusted based on a Medical Provider Network.
  • CO-P24 (Payment adjusted based on Preferred Provider Organization (PPO).): Adjusted based on a Preferred Provider Organization.
  • CO-P12 (Workers' compensation jurisdictional fee schedule adjustment.): A workers' comp jurisdictional fee schedule adjustment.
  • CO-131 (Claim specific negotiated discount.): A claim-specific negotiated discount, used when there's no standing network agreement.

CO-P26 FAQ

What is a Voluntary Provider Network?

A network providers choose to join under a contract, typically offering negotiated rates to participating P&C payers. Some state workers' comp systems distinguish voluntary networks from certified or mandated networks.

Where does the payer cite the contract?

At claim level, in the 835 class of contract code segment (loop 2100 REF). At line level, in the healthcare policy identification segment (loop 2110 REF), when regulations apply.

What if I don't recognize the network?

Ask the carrier or bill review company for the network name and your agreement. Network rental can extend a contract to carriers you didn't know about. Dispute it if no valid agreement exists.

Is CO-P26 a denial?

No. It reports a contractual reduction on a paid bill.

Is CO-P26 used by health plans?

No. X12 limits it to property and casualty claims.

Can I bill the claimant the VPN discount?

No. The discount comes from your network agreement, and X12 requires the CO group for this code, so it's the provider's adjustment.