Complete Guide to Letter of Undertaking (LUT) under GST: Maximizing Export Cash Flow & Compliance

Exporters operating under India’s Goods and Services Tax (GST) framework face a critical decision: should you lock up precious working capital paying Integrated Goods and Services Tax (IGST) upfront and waiting months for refunds, or should you streamline your cross-border operations using a Letter of Undertaking (LUT)?

Under Section 16 of the Integrated Goods and Services Tax Act, 2017, exports of goods and services as well as supplies to Special Economic Zones (SEZs) are classified as Zero-Rated Supplies. The law offers two operational mechanisms for zero-rated supplies:

1. Exporting on payment of IGST and subsequently claiming a tax refund.

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2. Exporting without payment of IGST by executing a Letter of Undertaking (LUT) or Export Bond.

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This comprehensive guide covers everything businesses, freelancers, MSMEs, and multi-national exporters need to know about the Letter of Undertaking under GST.

1. What is a Letter of Undertaking (LUT) under GST?

A Letter of Undertaking (LUT) is a legal declaration furnished in Form GST RFD-11 under Rule 96A of the CGST Rules, 2017. By submitting this form on the official GST portal, a registered exporter declares that they will fulfill all obligations prescribed under the GST law while exporting goods or services without paying IGST upfront.

                 +-------------------------------------------------+
                 |             GST EXPORT OPTIONS                  |
                 +------------------------+------------------------+
                                          |
                     +--------------------+--------------------+
                     |                                         |
                     v                                         v
      +------------------------------+          +------------------------------+
      |      OPTION 1: WITH LUT      |          |    OPTION 2: WITHOUT LUT     |
      |   (Form GST RFD-11 Filed)    |          |    (Pay IGST & Refund)       |
      +--------------+---------------+          +--------------+---------------+
                     |                                         |
                     v                                         v
      +------------------------------+          +------------------------------+
      |  Zero IGST Paid Upfront      |          |  Pay Full IGST Upfront       |
      |  Working Capital Preserved   |          |  Cash Blocked in Refund Cycle|
      |  Realization Clock: 1 Year   |          |  Wait Months for Processing  |
      +------------------------------+          +------------------------------+

The Legal Framework (Section 16 of IGST Act & Rule 96A)

• Section 16(1) IGST Act: Defines “zero-rated supply” as any export of goods or services or supply to an SEZ developer/unit.

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• Section 16(3) IGST Act: Mandates that a registered person making a zero-rated supply can export without payment of integrated tax upon executing an LUT or Bond.

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• Rule 96A CGST Rules: Outlines the exact procedure, conditions, time limits for export realization, and consequences of default.

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2. Why Every Exporter Needs an LUT: Key Benefits

Executing an LUT isn’t just about regulatory compliance; it is a vital cash-flow optimization tool.

+--------------------------------+-------------------------------------------------------+
| Strategic Advantage            | Impact on Business Operations                         |
+--------------------------------+-------------------------------------------------------+
| Cash Flow Preservation         | Prevents locking funds in IGST payments.|
| Eliminates Refund Delays       | Bypasses administrative waiting periods for refunds. |
| Administrative Efficiency      | Single annual filing covers all exports for the year. |
| Competitive Foreign Pricing    | Reduces working capital costs for flexible pricing. |
| Automated Instant Approval     | Deemed approval upon submission via GST Portal. |
+--------------------------------+-------------------------------------------------------+

3. LUT vs. IGST Refund Route vs. Export Bond

Exporters frequently ask whether they should file an LUT, pay IGST and claim a refund, or execute an Export Bond.

+------------------------+-------------------------------+-------------------------------+-------------------------------+
| Parameter              | LUT (Form GST RFD-11)         | IGST Payment & Refund         | Export Bond                   |
+------------------------+-------------------------------+-------------------------------+-------------------------------+
| Upfront Cash Requirement| Nil                           | High (18% to 28% of invoice)  | Nil                           |
| Working Capital Impact | Zero blocking                 | Severe blockage for 30–90 days| Zero blocking                 |
| Bank Guarantee Needed? | No                            | No                            | Yes (Up to 15% of bond)|
| Validity Period        | 1 Financial Year | Single Transaction            | Per transaction or running    |
| Primary Eligibility    | Clean tax record   | All registered exporters      | Prosecuted taxpayers |
| Approval Process       | Instant / Deemed  | Subject to Customs/GST audit  | Manual approval required      |
+------------------------+-------------------------------+-------------------------------+-------------------------------+

4. Eligibility Criteria for Filing LUT under GST

Under Notification No. 37/2017 – Central Tax, nearly all registered taxpayers exporting goods or services are eligible to file an LUT, provided they satisfy specific criteria:

1. Mandatory GST Registration

The business must possess an active GSTIN. Export of services is classified as an inter-State supply; hence, registration is essential to avail zero-rated treatment.

2. Intention to Make Zero-Rated Supplies

The entity must intend to export goods/services out of India or supply goods/services to Special Economic Zone (SEZ) units or SEZ developers.

3. Clean Legal Record (The Prosecution Bar)

The applicant must not have been prosecuted for any offense under the CGST Act, IGST Act, or any existing law where the amount of tax evaded exceeds ₹2.5 Crores (₹250 Lakhs). If an exporter has been prosecuted for tax evasion exceeding this threshold, they are barred from filing an LUT and must execute an Export Bond accompanied by a Bank Guarantee.

5. Conditions & Statutory Time Limits under Rule 96A

Filing an LUT provides tax-free export benefits, but exporters must strictly adhere to statutory timelines under Rule 96A.

+-----------------------------------------------------------------------------------------+
|                              STATUTORY COMPLIANCE TIMELINES                             |
+-----------------------------------------------------------------------------------------+
|                                                                                         |
|  [EXPORT INVOICE DATE]                                                                  |
|         |                                                                               |
|         +---> GOODS EXPORT: Must leave India within 3 MONTHS                           |
|         |     (If missed: Pay IGST + 18% interest within 15 days)               |
|         |                                                                               |
|         +---> SERVICE REALIZATION: Receive foreign payment within 1 YEAR             |
|               (If missed: Pay IGST + 18% interest within 15 days)               |
|                                                                                         |
+-----------------------------------------------------------------------------------------+

Timeline Rules for Exporting Goods

• Rule: The exporter undertakes that goods will be exported out of India within 3 months from the date of issue of the export invoice.

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• Default Penalty: If goods are not exported within 3 months, the exporter must pay IGST along with interest @ 18% per annum within 15 days.

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Timeline Rules for Exporting Services

• Rule: The exporter undertakes to receive payment for services in convertible foreign exchange (or INR where permitted by RBI) within 1 year from the invoice date.

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• Default Penalty: If payment is not realized within 1 year, zero-rating is revoked. The exporter must pay IGST along with 18% interest within 15 days. Failure to comply leads to withdrawal of the LUT facility.

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6. Documents Required for LUT Filing

Before logging into the GST portal, ensure you have the following information and documents ready:

1. GSTIN & Portal Credentials

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2. Authorized Signatory Details: Names, designations, PAN, and contact details of the proprietor, partners, MD, or CS.

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3. Digital Signature Certificate (DSC) or Electronic Verification Code (EVC): DSC is mandatory for Companies and LLPs; EVC (Aadhaar OTP) is available for Proprietorships and Partnerships.

4. Witness Information: Full names, occupations, and addresses of two independent witnesses.

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5. Previous Year LUT Copy: If renewing for a new financial year.

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6. Import Export Code (IEC): Necessary for physical goods export.

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7. Step-by-Step Guide: Filing Form GST RFD-11 Online

8. Validity, Renewal, and Post-Filing Compliances

LUT Validity Period

An LUT is valid for one entire Financial Year (from April 1 to March 31 of the respective year). Regardless of whether you file it on April 1 or December 15, the LUT expires on March 31 of that financial year.

Annual Renewal Cycle

Exporters must file a fresh LUT before the beginning of every new financial year (ideally in March for the upcoming FY starting April 1). Exporting goods or services on April 1 without a valid LUT registered for the new financial year forces you to pay IGST on those invoices.

LUT Filing Timeline Example:
+--------------------------------------------------------------------------+
|  Filed On:      April 2, 2026                                            |
|  Valid Until:   March 31, 2027                                           |
|  Action Required: File Renewal LUT for FY 2027-28 in late March 2027    |
+--------------------------------------------------------------------------+

Invoice Presentation Requirements

When issuing an invoice for zero-rated export under LUT, you must include specific regulatory statements. Include the following text prominently on the invoice:

“SUPPLY MEANT FOR EXPORT/SUPPLY TO SEZ UNIT OR SEZ DEVELOPER UNDER LETTER OF UNDERTAKING (LUT) WITHOUT PAYMENT OF INTEGRATED TAX (IGST)”

Additionally, mention your Application Reference Number (ARN) generated upon LUT submission.

9. Common Mistakes Exporters Make with LUT

• Forgetting Annual Renewal: Exporting on April 1 without renewing your LUT invalidates zero-rating for those invoices.

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• Missing the Invoice Compliance Declaration: Omitting the required LUT declaration on export invoices.

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• Ignoring the 1-Year Realization Clock: Failing to track foreign currency realization, exposing the business to 18% interest liabilities.

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• Incorrect Witness Details: Entering incomplete addresses or using internal business partners instead of independent witnesses.

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• Selecting the Wrong Jurisdiction: Selecting inappropriate state/central jurisdiction codes during initial registration.

10. Frequently Asked Questions (FAQs)

Q1. Is manual submission of Form GST RFD-11 required after online filing?

No. The online submission of Form GST RFD-11 on the GST portal is completely digital. Once you submit using DSC or EVC, an Acknowledgement Reference Number (ARN) is generated instantly, and the LUT is deemed approved.

Q2. Can a newly registered business file an LUT immediately?

Yes. As long as the business holds a valid GSTIN and its authorized signatory has not been prosecuted for tax evasion exceeding ₹2.5 Crores, a new entity can apply for an LUT right away.

Q3. What happens if payment for exported services is not received within 1 year?

Under Rule 96A, if foreign exchange is not realized within 1 year, the exporter must pay the applicable IGST along with 18% interest within 15 days. Once payment is realized, the LUT facility can be restored.

Q4. Does an LUT cover supplies made to SEZ units?

Yes. Supplies to Special Economic Zone (SEZ) units or SEZ developers qualify as zero-rated supplies under Section 16 of the IGST Act and are covered under the LUT facility.

Q5. Can freelancers and IT exporters use the LUT facility?

Yes. Independent service providers, software exporters, agencies, and freelancers providing services to clients abroad fall under export of services and benefit significantly from filing an LUT.