Reporting Account Number Changes
When account numbers change due to system migrations, card reissuance, or other operational reasons, you must report the change correctly to maintain credit history continuity for consumers.
1. When to Use Account Number Changes
Account number changes are required whenever a consumer's account identifier changes but the underlying tradeline remains the same. Common scenarios include:
Account Migration
Transferring accounts between systems, such as during a core banking platform migration or portfolio acquisition.
System Upgrades
Changing account numbering schemes during technology upgrades, such as expanding from 10-digit to 16-digit account numbers.
Card Reissuance
Issuing a new card number for fraud prevention, security breaches, or product changes while keeping the same credit line.
2. L1 Segment Overview
The L1 Segment is the Metro 2 mechanism for linking an old account number to a new one. It tells the credit bureaus that both numbers refer to the same tradeline, ensuring the consumer's payment history carries over seamlessly.
L1 Segment Fields:
┌─────────────────────────────────────────────────────┐
│ Field │ Length │ Description │
├──────────────────────────┼────────┼───────────────────┤
│ Segment Identifier │ 2 │ Always "L1" │
│ Change Indicator │ 1 │ 1 = New number │
│ New Account Number │ 30 │ The new number │
│ Old/Previous Account No. │ 30 │ The old number │
│ Balloon Payment Due Date │ 8 │ MMDDYYYY (if any) │
└─────────────────────────────────────────────────────┘Change Indicator Values
1Account number change — new identification number for existing account2Previously reported identification number3Combined account number (multiple accounts merged)3. How to Report the Change
When submitting an account number change, include both the old and new account numbers in a single submission. The Base Segment uses the new account number, and the L1 Segment carries the old number for reference.
Step 1: Update the Base Segment
Set the Account Number field (Field 3) to the new account number. All other fields should reflect the current account status.
Step 2: Attach the L1 Segment
Include the L1 Segment with Change Indicator = 1, the new account number, and the old account number. This links the two in the bureau's records.
Step 3: Submit Once
The L1 Segment only needs to be included in one reporting cycle. After the bureaus process the change, subsequent submissions should use only the new account number without the L1 Segment.
4. Maintaining History Continuity
The primary purpose of reporting an account number change is to preserve the consumer's credit history. Without the L1 Segment, the bureaus would treat the new account number as an entirely new tradeline, fragmenting the consumer's history.
With L1 Segment
- • Payment history is preserved under new number
- • Account age and open date remain accurate
- • Consumer score is unaffected by the change
- • Single continuous tradeline on credit report
Without L1 Segment
- • Old tradeline appears closed/lost
- • New tradeline starts with no history
- • Consumer score may drop significantly
- • Consumer may file disputes, causing extra work
5. API Example
Here is a JSON example showing how to include the L1 Segment when reporting an account number change via the Metro 2 API:
POST /api/v1/records
Content-Type: application/json
Authorization: Bearer your_api_key
{
"records": [
{
"accountNumber": "NEW-ACCT-9876543210",
"portfolioType": "I",
"accountType": "02",
"accountStatus": "11",
"currentBalance": 5200,
"scheduledPaymentAmount": 150,
"dateOpened": "2023-03-15",
"consumer": {
"name": {
"firstName": "Jane",
"lastName": "Smith"
},
"ssn": "***-**-1234",
"dateOfBirth": "1985-07-22"
},
"l1Segment": {
"changeIndicator": "1",
"newIdentificationNumber": "NEW-ACCT-9876543210",
"oldIdentificationNumber": "OLD-ACCT-1234567890"
}
}
]
}6. Common Mistakes to Avoid
Reporting the change every month
The L1 Segment should only be included in one submission. After the bureaus process it, use only the new account number. Repeated L1 Segments may cause processing errors.
Swapping old and new numbers
The Base Segment Account Number must be the new number, and the L1 Segment's Old Identification Number must be the previous number. Reversing them will corrupt the tradeline linkage.
Closing the old account separately
Do not report the old account number with a closed status in a separate record. The L1 Segment handles the transition. Reporting a closure separately creates a duplicate tradeline.
Omitting the L1 Segment entirely
Without the L1 Segment, the bureaus cannot link the old and new numbers. This results in a fragmented credit history that will likely generate consumer disputes.
Important
Report the account number change only once, then use the new number going forward. The L1 Segment is a one-time instruction to the bureaus—including it repeatedly may cause processing warnings or duplicate linkage attempts.
Related Resources
References
- • Metro 2 Format Guide - L1 Segment Specification
- • CRRG Section 6 - Account Identification
- • CDIA Metro 2 Format Documentation