CF 28 Inquiry: How to Respond Without an Excel Time Machine (19 CFR 163.4)

How do I respond to a CF 28 audit inquiry from CBP?

A CF 28 (Request for Information) requires the importer to produce contemporaneous documentation supporting the classification, valuation, country of origin, and tariff calculations on the affected entry. Under 19 CFR 163.4, importers must retain classification records for 5 years from entry. GingerControl's Product Sandbox Selection History writes the HTS candidate, country, configuration, and full tariff stack to a timestamped record every time a sourcing decision is committed, turning a CF 28 response from a forensic reconstruction into a copy-paste exercise.

What is the deadline to respond to a CF 28?

CBP typically gives 30 days from the date of the CF 28 to respond, though extensions can be requested. Failure to respond, or a response with insufficient documentation, can lead to a CF 29 (Notice of Action) and escalating compliance consequences including penalty action under 19 U.S.C. 1592 or rate liquidation against the importer.

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A CF 28 audit inquiry lands on the importer's desk eighteen months after the original entry was filed. The compliance team has thirty days to reconstruct: which HTS candidate was chosen, why, what country of origin was applied, what tariff stack was calculated, what valuation methodology was used, and what supporting documentation existed at the time of entry. Without contemporaneous records, the response becomes a forensic project across email, spreadsheets, broker correspondence, and human memory. GingerControl's Product Sandbox writes every committed sourcing and classification decision to Selection History with timestamp, configuration, and full tariff calculation, so the CF 28 response is a query against the record rather than an archaeological dig.

Last updated: May 2026

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What CBP Asks For in a CF 28

A typical CF 28 Request for Information asks the importer to provide [1]:

Category	What CBP wants
Classification documentation	The reasoning behind the HTS code chosen, including any GRI analysis, Section/Chapter Notes consulted, CROSS rulings cited
Country of origin documentation	Supplier certificates, rules-of-origin analysis (if FTA preference claimed), substantial transformation evidence
Valuation documentation	Commercial invoices, payment records, related-party pricing analysis, transaction value method support
Tariff calculation backup	Which tariff layers applied (Section 301, Section 232, Section 122, Chapter 99), rate determinations, supporting calculations
Communications	Broker correspondence, supplier emails, internal compliance notes from the time of entry

The standard for documentation is contemporaneous: produced at or near the time of the entry, not reconstructed after the CF 28 arrives. CBP auditors are trained to spot after-the-fact reconstruction [2].

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Why Spreadsheet-Based Records Fail at CF 28

A typical importer's classification record system is some combination of:

• Broker filing notes
• Internal Excel tracking sheets
• Email threads with suppliers
• ERP entry-summary data
• Compliance team meeting notes

When the CF 28 arrives, the team must stitch these into a coherent reconstruction for a specific entry on a specific date. Five recurring failures:

1. Tariff rates are not preserved at point-in-time. The Excel sheet shows "current" rates, not the rates in force on the entry date eighteen months ago.
2. HTS candidates considered but not chosen are lost. The "why we chose this HTS over the alternative" reasoning is rarely written down.
3. Country of origin analysis is buried in email. USMCA qualification logic, rules-of-origin determinations, substantial transformation evidence sits in inboxes that may no longer be accessible (departed employees, archived systems).
4. Valuation methodology is implicit. The fact that transaction value applied (vs. computed value, deductive value) is rarely documented explicitly per entry.
5. Configuration is not versioned. The compliance SOP in force at the time of entry may differ from the current SOP; without versioning, the audit response cannot demonstrate adherence to the contemporaneous standard.

The result: CF 28 response becomes a multi-week project consuming 20-100 hours of compliance team capacity, often with documentation gaps that lead to adverse audit findings.

GingerControl is AI global trade compliance infrastructure that helps importers, exporters, and customs brokers classify products, engineer optimal tariff positions, calculate duties, and track policy changes. Product Sandbox Selection History is built around the contemporaneous-documentation standard CBP applies to CF 28 audit responses.

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What Selection History Captures

Every committed selection in Product Sandbox writes to Selection History with [3]:

Field	What it captures
Timestamp	Exact UTC time the selection was committed
HTS candidate	The 10-digit HTSUS code chosen plus all candidates considered
Country of origin	The country selected for the entry
Tariff stack configuration	Section 301, 232, 122, Chapter 99 applicability flags as of the entry date
Full tariff calculation	MFN base, surcharges, MPF, HMF, total landed cost as calculated
FTA preference status	Whether FTA preference was claimed, under which agreement, with documentation links
Valuation method	Transaction value, computed value, or other methodology
Reasoning notes	Free-text notes captured at decision time
Configuration version	Which version of the compliance SOP was in force at decision time

The audit-ready output for a single entry looks like a structured record: "On 2026-04-15 at 14:32 UTC, HTS 7326.20.00 was selected for product Industrial Steel Wire Rack from origin China at 25% Section 232 plus 25% Section 301 plus 10% Section 122. Reasoning: ..."

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How Selection History Maps to a CF 28 Response

A CF 28 response template, mapped against Selection History fields:

CF 28 question	Source in Selection History
"What HTS classification was used?"	HTS candidate field
"What is the reasoning for that classification?"	Reasoning notes + Classifier handoff record
"What rate of duty was applied?"	Full tariff calculation breakdown
"What is the country of origin?"	Country selection field
"Was preference claimed under an FTA?"	FTA preference status
"What valuation method was used?"	Valuation method field
"Provide supporting documentation"	Linked Classifier research record + supplier certificates

The response is a structured extract from the record, not a reconstruction.

GingerControl's HTS Classification Researcher follows GRI logic, surfaces multiple candidate HTS codes, and asks clarifying questions before converging on a classification, producing audit-ready reports grounded in Section Notes, Chapter Notes, and relevant CROSS rulings. Selection History is the layer that captures the Classifier's output plus the sourcing decision into one timestamped record.

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19 CFR 163.4 Compliance

19 CFR 163.4 requires importers to maintain records relating to importation activities for 5 years from the date of entry [4]. The covered records include:

• Entry records
• Classification records (HTS, country of origin)
• Valuation records
• FTA preference documentation
• Drawback records

The retention standard requires that records be available for inspection by CBP. Paper records, electronic records, and cloud-hosted records all qualify if they are retrievable on request.

Selection History meets the retention standard automatically: every committed decision writes to durable storage with timestamp, the data is exportable on demand, and the 5-year retention is handled at the platform level rather than requiring manual archival processes.

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Beyond CF 28: Focused Assessments and 1592 Penalty Defense

Selection History supports more than CF 28 inquiries. In:

• Focused Assessments (CBP's primary audit program), the audit team samples entries and asks the same contemporaneous-documentation questions. Selection History feeds the sample queries directly.
• 19 U.S.C. 1592 penalty defense, the distinction between negligence (2x revenue loss) and gross negligence (4x) often turns on whether the importer can demonstrate procedural diligence. Per-entry Selection History records are the procedural evidence.
• Prior disclosure submissions under 19 U.S.C. 1592(c)(4), where the importer voluntarily discloses misclassification, Selection History documents what was known when, which affects the disclosure's voluntary character.

The same record system serves all four CBP audit pathways. The compliance team builds it once and uses it for years.

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Frequently Asked Questions

What is a CF 28 Request for Information?

A CF 28 is CBP's formal request for documentation supporting a specific entry. It typically asks about classification, valuation, country of origin, or tariff calculation on the affected entry, with a 30-day response window.

What records must I keep for CBP under 19 CFR 163.4?

Entry records, classification records, valuation records, FTA preference documentation, drawback records, and related correspondence. The retention period is 5 years from the date of entry.

What happens if I cannot produce the records CBP requests?

CBP can issue a CF 29 (Notice of Action) escalating the issue, or proceed directly to penalty action under 19 U.S.C. 1592. Documentation gaps typically push penalty exposure from negligence (2x revenue loss) to gross negligence (4x).

How long do I have to respond to a CF 28?

30 days from the date of the CF 28, with possible extensions if requested in writing before the deadline. Late responses carry the same documentation-gap consequences as no response.

What does Selection History capture that a spreadsheet does not?

Timestamp on every decision, configuration version, full tariff calculation as applied (not as recalculated later), FTA preference status, valuation method, and candidate HTS codes considered but not chosen. The point-in-time accuracy is what spreadsheets structurally cannot provide.

Can Selection History be exported for the audit response?

Yes. Selection History supports export to PDF or structured data formats for inclusion in the CF 28 response, with timestamp and configuration data preserved.

Does Selection History also support Focused Assessments?

Yes. The same record structure that supports CF 28 responses supports Focused Assessment sampling, prior disclosure documentation, and 19 U.S.C. 1592 defense.

How does Selection History work with my licensed customs broker?

The broker can access Selection History as part of the importer's record system, pulling extracts for inclusion in CBP responses without having to reconstruct from broker filing notes alone.

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Build the Audit Trail Before the CF 28 Arrives

If your team has ever spent weeks reconstructing a classification decision from emails, broker notes, and ERP entry summaries, the structural issue is that the records were not built for contemporaneous audit response. Product Sandbox at gingercontrol.com/products/product-sandbox writes every committed decision to Selection History with timestamp, configuration, and full tariff stack. When the next CF 28 lands, the response is a query, not a reconstruction.

If you want to evaluate your overall audit-readiness first, take the GingerControl compliance audit quiz for a quick assessment of where your CF 28 and Focused Assessment preparation stands today.

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Related Articles

• Reasonable Care Under 19 U.S.C. 1484: How AI Classification Tools Fit In
• How to Build an HTS Classification Governance Program for Automated Tools
• CBP Focused Assessment Preparation
• Prior Disclosure to CBP: When and How to Use 19 U.S.C. 1592(c)(4)

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References

[REF 1] CBP, Form CF 28 Request for Information Process Source: CBP Trade Forms

[REF 2] CBP, Focused Assessment Program Source: CBP Focused Assessment

[REF 3] GingerControl Product Sandbox Product Page Source: Product Sandbox

[REF 4] 19 CFR 163.4, Record Retention Source: eCFR 163.4

[REF 5] 19 U.S.C. 1592, Penalties for fraud, gross negligence, and negligence Source: Cornell LII