The REG 51 Report of Sale is one of the most important controlled forms in a California used vehicle retail deal jacket. When it is completed clearly, submitted on time, and controlled in sequence, it helps reduce DMV rejects, audit findings, and avoidable penalty risk. For students preparing for the California DMV dealer test or dealers renewing a license, REG 51 compliance is a must-know topic.

Think of the REG 51 as more than a form. It is a compliance checkpoint that connects the vehicle, purchaser, sale date, temporary identification, DMV notice, and dealer records. A small error in the vehicle identification number, date sold, buyer information, or form sequence can create unnecessary follow-up with DMV and confusion in your records.

What the REG 51 Report of Sale Is Used For

California licensed dealers use the Report of Sale–Used Vehicle, REG 51, to report the retail sale of used vehicles. The California DMV explains that the REG 51 is used for retail used vehicle sales, but it is not used to report sales to wholesale dealers or sales of vessels.

Because REG 51 forms are controlled, they should be treated like accountable inventory. Access should be limited, form numbers should be tracked, and voided or replacement forms should be documented. Dealers obtain additional REG 51 forms through DMV Occupational Licensing, using the DMV order process identified for used report of sale forms.

When the Sale Date Starts the Clock

For REG 51 purposes, the sale date is not simply the day paperwork is printed. The key concept is when the sale is consummated. DMV guidance ties the date sold to the point when the buyer has paid the purchase price or signed a purchase contract or security agreement and has taken possession or delivery of the vehicle.

That date matters because the dealer notice portion must be mailed no later than the fifth calendar day after the sale date, not counting the actual date of sale. Build your dealership workflow around that deadline. Waiting until the title clerk has every item in the file can create risk if the notice portion has not been handled separately and on time.

REG 51 Completion Checklist

Use this checklist before the purchaser leaves and again before the dealer notice is mailed:

• Confirm the correct REG 51 number is being used in numerical sequence.
• Verify the date sold using the consummated sale rule: payment or contract plus possession or delivery.
• Match the VIN, year, make, model, body type, and license or temporary identification information to the source documents.
• Enter purchaser information clearly and consistently with the contract and title application documents.
• Use typed, computer-generated, or legible hand-printed entries. If handwriting is used, block upper case letters are preferred for clarity.
• Review all copies so the vehicle description and purchaser information are accurate on each part of the form.
• Separate and route each REG 51 copy according to DMV distribution requirements.
• Retain the dealer copy in the dealership records for the required retention period.

Five-Day Dealer Notice Workflow

The dealer notice is a time-sensitive part of the REG 51 process. DMV guidance states that the dealer notice must be mailed to the DMV address shown on the REG 51 no later than the fifth calendar day following the sale date, excluding the date of sale. The notice cannot be submitted to a DMV field office.

A simple internal process can prevent missed deadlines:

1. Assign responsibility for pulling the dealer notice immediately after delivery.
2. Stamp or log the sale date and the mailing deadline.
3. Mail the notice to the address shown on the REG 51, not to a field office.
4. Record the mailing action in the deal jacket or a report-of-sale log.
5. Review open deals daily for any unmailed notices before the fifth-calendar-day deadline.

Controlled-Form Handling: Treat REG 51 Like Accountable Inventory

The REG 51 is a controlled DMV form, so it should never be left unsecured or used out of order. DMV guidance requires REG 51 forms to be used in numerical sequence. A missing number, unexplained void, or out-of-sequence form can raise questions during an internal review or DMV inspection.

Common REG 51 Mistakes That Cause Problems

Most REG 51 errors are preventable. Train your team to slow down at the handoff between sales, finance, and title processing. Watch for these issues:

• Using the contract date even though the buyer took delivery on a different date.
• Submitting the dealer notice late because the deal jacket was waiting for other documents.
• Entering an incorrect VIN, plate number, year model, or purchaser name.
• Using forms out of numerical sequence.
• Leaving handwriting unclear or inconsistent across copies.
• Failing to document a voided or replacement REG 51.
• Trying to submit the dealer notice to a DMV field office instead of mailing it as directed.

Corrections, Lost Forms, and Voids

If a mistake is discovered, do not ignore it or create an undocumented workaround. DMV guidance allows corrections on the REG 51, but the correction must be approved and initialed by the dealer or authorized representative who signed the dealer certification. Odometer disclosure errors require special handling and may require a separate Vehicle/Vessel Transfer and Reassignment Form and a Statement of Facts.

If a completed REG 51 is lost before submission, DMV provides an “in lieu of” process that includes a new REG 51 marked as a replacement for the original report number, completed with the same information, plus supporting documentation. If a REG 51 was completed in error and the sale was not consummated, DMV guidance calls for marking all parts void and completing a Statement of Facts explaining the error.

When a REG 51 Is Not Required

Not every dealership action involving a used vehicle requires a REG 51. DMV guidance states that a dealer is not required to complete a report of sale when registering a used vehicle solely in the dealership’s name. DMV also identifies certain non-highway children’s vehicles, such as midget autos or racers advertised as built exclusively for children, as examples where a report of sale is not required.

Also remember that the REG 51 is not the form for wholesale dealer sales or vessel sales. Using the wrong report of sale form can create documentation issues, so confirm the transaction type before completing the paperwork.

Mail Order and Nonstandard Delivery Situations

Mail order and other nonstandard delivery scenarios deserve extra attention because the sale date and delivery facts drive the REG 51 timeline. The safest practice is to document when the buyer signs the required agreement, when payment or financing is completed, and when the buyer receives possession or delivery. Then apply the REG 51 deadline from the correct sale date.

If your dealership handles out-of-state delivery, export, private-property use, IRP-related transactions, or title-only/transfer-only situations, review the applicable DMV procedure before attaching or distributing copies. These transactions may have special report-of-sale handling requirements.

Audit-Ready REG 51 File Review

Before closing a deal jacket, perform a quick audit review. This helps catch problems while the transaction is still fresh and staff can still locate supporting documents.

• Does the REG 51 number match the dealership log?
• Was the form used in numerical sequence?
• Does the date sold match the delivery and contract facts?
• Was the dealer notice mailed by the fifth calendar day after the sale date, excluding the sale date?
• Do the vehicle and purchaser details match the title application, contract, and odometer documents?
• Is the dealer copy retained in the dealership records?
• Are corrections, voids, or replacement forms fully explained?

Dealer Test Takeaway

For exam preparation and day-to-day compliance, remember the core REG 51 rules: use it for California retail used vehicle sales, complete it clearly and accurately, use controlled forms in numerical sequence, mail the dealer notice by the fifth calendar day after the sale date, and retain the dealer copy for four years. If your dealership builds these steps into a checklist, REG 51 compliance becomes a repeatable habit instead of a last-minute scramble.

Sources

• California DMV Vehicle Industry Registration Procedures Manual: Report of Sale Used Vehicles, General Information
• California DMV Vehicle Industry Registration Procedures Manual: Report of Sale Used Vehicles, Mail Order Sales
• California DMV Vehicle Industry Registration Procedures Manual: Corrections on the Report of Sale–Used Vehicle REG 51
• California DMV Vehicle Industry Registration Procedures Manual: “In Lieu of” Report of Sale–Used Vehicle
• California DMV Vehicle Industry Registration Procedures Manual: Void Report of Sale