Metro 2 Account Type Code 01: Unsecured Loan

Specification

Code	01
Meaning	Unsecured Loan
Field	Account Type (Field 15)
Record	Base Segment
Length / position	2 chars · 84–85
Category	Consumer Installment Loans
CRRG reference	CRRG Exhibits 1 & 2 (Account Type Codes)

The defining fact is the absence of collateral. If the lender can only pursue the borrower personally on default, this is the code.
Fixed amount, fixed term, fixed payment. It is not a personal line of credit the borrower can redraw, which is code 15.
A cosigner or guarantor does not make a loan secured. An unsecured loan with a cosigner is still 01, with the cosigner carried in ECOA and a J1 or J2 segment.
Does NOT mean unsecured revolving debt. An unsecured credit card is 18, not 01, because the product shape and Portfolio Type differ.
A loan that started secured and lost its collateral (the vehicle was surrendered, the deposit was released) does not become 01. The account type is set by the original product.

1A bank reports a 36-month $12,000 signature loan used for debt consolidation.
2A fintech marketplace lender reports a fixed-rate personal loan funded through an issuing bank partner.
3A credit union reports a small-dollar signature loan to a member with no share pledge behind it.
4An employer-affiliated lender reports a fixed-term unsecured advance repaid by payroll deduction.
5A retailer's finance partner reports an unsecured fixed-payment installment plan not tied to specific merchandise.

Do not report a share, deposit, or title pledge in any field on an 01 tradeline. If collateral exists, the correct code is 02 or 03.
Populate Original Loan Amount in Highest Credit and leave Credit Limit zero-filled.
Report the contractual Scheduled Monthly Payment, not the amount the borrower happened to pay. Actual Payment Amount carries what was received.
Use 15 instead if the borrower can draw the balance back up after paying it down.
Once the loan is paid, report Account Status 13 with a zero Current Balance and a populated Date Closed rather than dropping the tradeline from the file.

A file can be structurally valid and still be wrong. These are the cross-field conditions Account Type Code 01 has to satisfy.

Portfolio Type must be I (Installment), which requires both Scheduled Monthly Payment Amount and a numeric Terms Duration in months.
Credit Limit must be zero-filled. A populated Credit Limit signals a revolving or line-of-credit product and contradicts Portfolio Type I.
Highest Credit / Original Loan Amount should equal the amount financed at origination and should not change over the life of the loan.
Terms Frequency is typically M. Any frequency other than a periodic one is inconsistent with an amortizing installment note.
A cosigner is expressed through the ECOA Code (2 for joint, 3 for authorized user is wrong here, 5 for cosigner-style association depending on the relationship) and the J1 or J2 segment, never by changing Account Type.
If the loan is later sold, the buyer's tradeline carries the K1 segment naming the original creditor while your tradeline reports Account Status 05 with a zero balance.