CARM mass adjustments: fixing many CAD lines at once, including pre-CARM B3s

When does one mass adjustment beat many single adjustments?

An audit that finds the same error on many lines faces a filing choice. CBSA Memorandum D17-2-1 defines a mass adjustment as "an adjustment to two or more commercial accounting declarations (CADs) for the same legislative issue for up to three reasons". In the CARM Client Portal, you pick the level (header, invoice or commodity line), select the CADs, change the field once, and the change is applied to every CAD you selected. Each CAD gets a new version and its own Statement of Adjustment.

Customs Notice 26-03, effective February 2, 2026, tightened the rules. Read together, the two documents give a simple test:

The notice's own example of "same change" is strict: a change from tariff item 0805.10.00.10 to 0804.40.00.00 must apply to every line in the case, and "You cannot include other tariff classification changes in the same request." Two different reclassifications are two cases.

What the mass route saves is work and timing risk. One case number, one form, one upload, and one filing date for every CAD in it. What it costs is all-or-nothing exposure: Customs Notice 26-03 says that if the same changes do not apply to all lines, "the mass adjustment case will be rejected and time limits will not be protected".

What does Form BSF987 ask for?

Customs Notice 26-03 requires Form BSF987, Mass Adjustment Request Form, to be completed and uploaded to the mass adjustment case in the portal. The form asks for:

• the CARM case number, and the CBSA verification number if the case follows a verification;
• the importer's BN/RM and the location of books and records;
• the authorized agent, if any, and a contact;
• whether the adjustments are "Amount Owing to CBSA or Revenue Neutral Changes" or "Amount Resulting in Refund";
• reason codes 1 to 3;
• the reason and justification for the request;
• a declaration that the reason codes apply to all CAD lines in the case and that the information is true, accurate and complete.

The tick boxes are where cases fail. Ticking "applies to all CAD lines" on a case where one line nets the other way is the rejection Customs Notice 26-03 describes.

How do reason codes and their order work in a mass case?

A mass adjustment may carry up to three reason codes, and since February 2, 2026 they may come from more than one legislative issue. D17-2-1 already allowed the common pairing of a classification change with the tariff treatment or origin change it causes. Customs Notice 26-03 sets the order so interest is calculated correctly: when the lines result in a refund, the refund code goes in commodity reason code 1; when they result in an amount owing or no revenue change, the code supporting that result goes first. The codes themselves, finding by finding, are in CARM adjustment reason codes.

What are the filing mechanics and the documents rule?

1. Generate a case. In the portal you can build the mass adjustment directly. For EDI or API filers, D17-2-1 says to generate a mass adjustment case number in the portal first and then transmit every CAD in full, referencing it, within 5 business days, or the CBSA closes the case.
2. Upload BSF987 to the case.
3. Upload documents if the rule requires them. For a mass adjustment that results in a refund and covers fewer than 25 CADs, D17-2-1 requires documents for each CAD, uploaded by 11:59:59 pm Eastern on the day of submission. At 25 CADs or more, documents need not go in on the day, but must be readily available and produced by the deadline the CBSA sets, or the case may be rejected.
4. Watch the case. Customs Notice 26-03 says a rejected case has its status set to "Rejected", the CADs referred for review are rejected individually, no Statement of Adjustment is produced for them and the reason arrives as an ad hoc notification in the portal. CADs already processed without review keep their Statements of Adjustment.

After a CBSA trade compliance verification, D17-2-1 says the importer may be required to submit adjustments within 90 days of the Trade Compliance Verification Report and must reference the case number on the Directed Compliance Letter, Compliance Validation Letter or final report. A mass adjustment is allowed for these.

How do you adjust a B3 from before CARM?

Goods accounted for on Form B3-3 before October 21, 2024 are outside D17-2-1. Memorandum D17-2-4 gives two routes, and Customs Notice 24-25 confirms that Form B2 was not accepted from October 21, 2024.

Route 1: convert, then adjust. Create a pre-CARM "as declared" CAD for each B3 by asking the CARM help desk, choosing "Convert B3 to CAD" on the portal's Create Declaration page, or querying the API. Check the returned data, fill in what is missing, and bring it up to date with any adjustment the CBSA already approved, such as an earlier blanket B2 or a drawback. D17-2-4 warns that section 7.1 of the Customs Act applies: false or inaccurate as-declared data brings penalties, and a CAD that does not match the B3 gets the adjustment rejected. The as-declared CAD posts to the account but creates no amount owing. You then adjust it like any CAD, singly or in a mass adjustment. This is the route the CBSA encourages.

Route 2: the Pre-CARM Blanket Request. When 100 or more B3 transaction lines within a 12-month period need adjusting and no as-declared CAD exists for any of those B3s, D17-2-4 allows one blanket request instead of converting each one. The conditions:

• all lines share the same legislative issue and up to three reasons (classification plus its tariff treatment or origin change is allowed);
• no SIMA issue combined with other issues;
• not for tariff rate quota classifications, licensed goods, overages, section 60 or 61 requests, appeals under sections 67 and 68, or lines whose time limit has passed;
• filed only through the portal: generate a mass adjustment case number, select "submit", then upload Form BSF957, Pre-CARM Blanket Adjustment Request Form, and the workbook within 5 business days.

The workbook rules are specific. Lines go in chronological order of accounting date. Each calendar year goes on its own worksheet. GST owing to the importer and GST payable to the CBSA cannot offset each other and go on separate worksheets. Amounts owing of CAD 7.50 or less per transaction must be taken out to benefit from the Customs Accounting Document Error Remission Order (Memorandum D17-1-9), and refunds under CAD 2.00 per transaction are left out because the Low-Value Amounts Regulations stop the CBSA from paying them.

BSF957 itself states that uploading the form and workbook "constitutes filing an adjustment request under Section 32.2, 74 or 76" and that the upload date "is considered the legislative submission date". D17-2-4 adds that the same date stops the section 32.2 90-day clock, and that if the workbook is rejected, the 90 days resume from the rejection date.

What happens after a blanket is filed?

D17-2-4 describes the processing:

• No payment with the request. An amount owing under section 32.2 is paid only after the CBSA posts the adjustment.
• One consolidated CAD. The CBSA creates a pre-CARM "as declared" type F CAD with all the B3 lines and adjusts it from the workbook's "as claimed" values. Duties and taxes owing or refundable post to the account.
• Interest on a separate invoice. Interest appears on the Statement of Adjustment but posts as a Form K23, Miscellaneous Invoice. Both follow the standard billing period for payment.
• A median start date. Interest runs from the median date between the first and last transaction in each year; if the period has an even number of days, the day after the median.
• No later edits. The approved changes are not reflected on the individual B3 transactions, and the consolidated CAD cannot be adjusted again. A later fix to one of those transactions needs its own as-declared CAD that carries the blanket's change.
• Appeal by section 60. The blanket decision is appealed through the standard re-determination process in Memorandum D11-6-7.

How does it work on one audit with 318 lines?

An importer's audit covers January 2024 to March 2026 and finds two problems. The values and rates are illustrative.

• Problem 1: a part was entered under a tariff item at 0% when it belongs under an item at 6.5%. It appears on 120 B3 lines accounted for between January 8 and October 14, 2024, and on 180 lines across 60 CADs since then. Underpayment.
• Problem 2: a 25% surtax was charged on 18 lines across 12 CADs whose origin is not covered by the order. Overpayment.

The filing plan:

Group B qualifies for the blanket because it has 120 B3 lines inside one 12-month period and the importer converts none of them first. Its lines span January 8 to October 14, 2024, 281 days counting both ends, so interest runs from the median date, May 27, 2024. Group C cannot join group A because the result differs: a refund case and an amount-owing case are separate under Customs Notice 26-03. Group C's GST does not come back as a CBSA credit: D17-2-1 says GST registrants recover it as an input tax credit, and non-registrants apply to the Canada Revenue Agency with the Statement of Adjustment.

Filing groups A and B on the same day stops the 90-day clock for problem 1 on all 300 lines. Group C has no 90-day clock, but every month of delay pushes its oldest lines toward the four-year limit in subsection 74(3) of the Customs Act.

Which mistakes sink a mass case?

• One line that nets the other way. It turns a valid case into a rejected one.
• Two different new values for the same field. Two reclassifications are two cases.
• A correction mixed with an adjustment. Customs Notice 26-03 forbids it.
• A missing BSF987. Required since February 2, 2026.
• Late EDI transmission. CADs not sent within 5 business days of the case number close the case.
• A blanket that includes a converted B3. D17-2-4 rejects the whole request.
• Lines past four years. Subsection 32.2(4) ends the correction obligation four years after accounting, and refund claims for most grounds are out of time after four years. Expired lines in a blanket make it ineligible.

What should you do next on your own entries?

Group your audit findings before anything is filed: by change, by direction, by reason codes, and by CAD or B3. That grouping is the filing plan, and it shows which findings can share one filing date. TariffSense audits CAD and B3 lines against the measures in force on each date, gives every finding its direction and corrected values, and groups lines that share a change and a result, so the mass case or blanket workbook can be built from the list. The section 32.2 and section 74 rules behind each route are in correcting a Canadian entry, and an underpayment found late can go through the CBSA voluntary disclosures program. See the post-entry audit page for what goes in and what comes back. Confirm the filing with your licensed customs broker.