GST Issues in Construction Milestone Billing: Tax Treatment, Compliance Challenges, and Best Practices

Introduction : The construction and infrastructure industry has long-term contracts, which involve a staggered delivery of goods/services and payments made against such delivery. Milestone billing is sometimes used as a method of payment which means that payments are due upon the completion of specific stages of the work such as foundation, superstructure, systems installation, completion and handing over the project for use by the employer. While this is good for ensuring that both parties have received and paid for work performed, it can be very challenging from a GST perspective due to differences between the commercial terms and GST law.

This article discusses the implications for GST compliance on construction contracts which use milestone billing, advance payments, and retention as a method of payments by exploring the relevant statutes, case laws and practical implications of such billing arrangements. Issues with Milestone Billing and GST Compliance: When a business makes a supply of goods or services they normally expect to receive payment either when ownership of goods changes hands or after the service has been delivered. However, in a construction contract using milestone payments, the billing schedule only allows a part payment until certain deliverables have been met. The issues which arise most often include the following:

A. The taxability of mobilization advance and retention money

B. The timing of GST liability in relation to the retention money

C. The application of GST law on continuous supply of services such as construction on a contract hire or continuous basis as opposed to one-time contracts. The implications of these problems are that contractors who have received advances and retainers can be asked to pay tax, interest, and penalties on amounts due to them because GST was charged too late. In addition, differences between project accounts, running account invoices, and GST returns can cause tax assessments and disputes. A closer look at the GST treatment of construction contracts under different billing arrangements. In view of the foregoing issues, this article will discuss:

A. Statutory framework including case laws on a range of issues including valuation, timing of supply, and invoicing

B. The GST treatment of advance payments including mobilization advance

C. The GST treatment of retention money and application of tax on retention

D. The lessons learned and practical implications.

This article is a comprehensive guide to the implications of GST compliance for construction contracts and other long-term agreements involving continuous supply of goods and services. It examines the statutory framework, case laws, and various practical implications for GST compliance by analysing advance payments and retention money.

Legal Provisions

A. Works Contract as Supply of Services: Section 2(119) of the CGST Act, 2017

A works contract for construction, erection, installation, completion, fitting-out, repair, maintenance, renovation, alteration or commissioning of an immovable property in relation to such property comprises the supply of service. Schedule II, Entry 6(a) states that the supply of works contracts shall be deemed to be supply of services. Significance: Due to this inclusion of works contract as supply of services, the time of supply of services is deemed to be the time when services are completed. Thus the provisions relating to time of supply of services are applicable to work contract for determining the time when tax is liable to be paid.

B. Time of Supply of Services: Section 13 of the CGST Act, 2017

GST becomes payable on the earliest of the following date namely:-the date of issue of invoice, the date of receipt of payment, or the date as may be prescribed in the Act in case of invoices not issued within the specified period. However, in case of a contract of a construction of a building on a percentage completion basis, GST shall become payable on receipt of advance payments even if the construction activity has not been completed.

C. Tax Invoice Requirements: Section 31 of the CGST Act, 2017

A registered supplier is required to issue a tax invoice for supplies of goods and services subject to tax within the specified period. In the case of continuous supply of services, invoices are issued on completion of a contract milestone, on occurrence of any specified event or on receipt of payment from the recipient, as may be agreed upon the parties.

D. Receipt Voucher for Advances: Section 31(3)(d) 

Where an advance consideration has been received, the registered person to whom it is paid shall issue a receipt voucher acknowledging receipt thereof.It will be pertinent to mention here that in case of construction contracts, the receipt of mobilisation advance or booking advance is often required to be made before the commencement of work.

E. Value of Supply: Section 15 of the CGST Act

The value of supply shall include the consideration received or receivable in respect of supply of goods or services, any amount which the supplier is liable to pay but which is received or payable by the recipient, and any incidental expenses incurred by the recipient in relation to the supply. Thus, the treatment of retention money may have to be examined under this section.

Legal Analysis

A. GST on Mobilisation and Other Advances: Nature of Mobilisation Advances

Construction contracts often provide for mobilisation advance to meet mobilisation charges which enables the contractor to mobilise labour, machinery, equipment and material at the site. A taxpayer’s view is that GST would become payable on receipt of such mobilisation advances against the completion of the specific work in the contract. However, GST law takes the position that mere receipt of consideration triggers tax liability.

B. Time of Supply Consequences

As works contract falls under service, receipt of any advance shall result in liability to pay GST at the time of receipt as upheld by courts on various occasions. Mobilisation advance is consideration for future supply of goods or services and, therefore, taxable as soon as it is credited or received.

C. Compliance Requirements

The following actions are due upon receipt of advance: receipt voucher must be issued. GST must be paid in the period in which it has been received adjustment entry must be made in the books of account in respect of such mobilisation advances received in order to avoid interest liability. Non-payment of GST on advances would lead to interest levy and mismatch in project accounts and GST liability.

D. Continuous Supply of Construction Services

Construction contracts generally qualify as continuous supply of services due to their long-term nature and periodic payment structures. A typical milestone schedule may include:

Excavation completion;Foundation completion; Structural completion; Roofing completion; Finishing stage; Final handover. Each milestone effectively represents a taxable event for invoicing purposes.

E. Completion-Linked Billing

Where the contract specifies that payment becomes due upon completion of a milestone, GST liability generally arises when the invoice is issued or when payment is received, whichever occurs earlier. Businesses must ensure that project engineers, finance teams, and GST compliance teams operate in coordination. Delays in raising milestone invoices often create timing differences between revenue recognition and GST reporting.

Relevant Case Laws

1. S.P. Singla Constructions Pvt. Ltd. – Gujarat AAAR: Issue raised was whether GST is payable on receipt of mobilisation advance or on adjustment against subsequent bills. The Appellate Authority concluded that mobilisation advances are consideration for supply of services by way of construction. Thus, GST is payable on the date of receipt of such advances in accordance with Section 13 of the CGST Act. The Authority rejected the plea that mobilisation advances received merely represent deposits. Principle Established was Mobilisation advances are not mere deposits and GST thereon is exigible on receipt.

2. Sankaranarayana Constructions Pvt. Ltd. v. Commissioner of Central Tax: Taxability and timing of GST on mobilisation advances in construction contracts. The Tribunal was of the view that GST is applicable to mobilisation advances relating to construction of civil structures and that the time of supply provisions of Section 13 apply to such advances. Principle Established was that advances in respect of construction of civil structures attract GST prior to accomplishment of the relevant milestones.

3. Dholera Industrial City Development Ltd. (AAR): Issue raised was whether charges for failure to achieve project milestones are consideration for supply of services. The Authority noted that certain damages for failure to meet project milestones would not necessarily be consideration for a taxable supply. Principle Established was that there is a need for distinguishing between consideration for supply and compensation for failure to perform contractual obligations in respect of a project.

Practical Implications

The treatment of construction milestone billing under GST has several implications for contractors, developers, and construction companies. First, since GST is payable on receipt of advances or issuance of milestone-related invoices, it can lead to cash flow issues for businesses as they may be required to pay tax even when the consideration for goods/services is yet to be received. Moreover, as retention money is generally withheld from payment till the completion of a project or expiry of defect liability period, GST is payable on the gross invoice value despite the fact that a portion of the consideration is yet to be received. In addition, differences between project accounting, revenue recognition and GST accounting can lead to discrepancies in books of accounts, RA Bills, GSTR-1 and GSTR-3B. Inconsistencies also arise due to delays in certification of milestones, invoices or adjustments of advances. As a result, businesses engaged in construction need to implement strong internal controls and ensure that project management and finance teams are aligned on the timelines for raising invoices, issuing RA Bills and GST filings. They must also perform regular reconciliations to avoid disputes and additional tax liabilities.

• Cash Flow Issues: A contractor may have to pay GST on cash even if he has not received cash as; There was retention of amounts and approvals for milestones were delayed payment was yet to be certified. This may affect the working capital of the company.

• Advance Receipt: Many companies wrongly delay paying GST on advances received till the completion of the milestone. As a result, they may face, interest under section 50, demand of GST, adjustment in return etc.

• Revenue Recognition As per accounting standards, revenue may be recognised at a point when the contract is at a certain level of completion, whereas tax may be triggered on receipt of advances certification of milestones issuance of invoices. There may be scope for reconciling revenues as per books of account and GST. Some common discrepancies observed in GSTR1 and GSTR3B are as below,

A. Advances not recorded; Advances received are shown in books of account but not declared in GST returns.

B. Double charging of tax: Payment of tax on advances received and double charging of tax on invoice value without adjustin the advances.

C. Wrong treatment of retention: Retention money received is not added to the value of supply.

D. Delay in raising invoices: While project teams are able to get approvals for milestones, finance teams may not be able to raise invoices beyond certain milestones within the due dates.

E. Discrepancies in RA bill: There may be mismatches between work completed and certified, revenue recognised, invoices raised, tax declared. Such discrepancies are often picked by the department for scrutiny.

Way Forward: Strengthening Billing Controls in Construction Projects

Due to the identified compliance issues related to billing practices of construction projects, it is essential for organisations to implement strong control procedures in order to reduce GST exposure and improve tax reporting accuracy. Before preparing GST returns, companies need to ensure that contract documentation stipulates all milestones, advance payments, and retention money, as well as thoroughly checking that all advances have been correctly received with proper receipt vouchers, GST amount deducted, and subsequent adjustments made against invoices issued on milestones accomplishment. In addition, it is necessary for organisations to establish appropriate control procedures over milestones to make sure that completion certificates and approvals have been acquired from relevant stakeholders and invoices issued are not overdue. Such steps might help construction companies prevent GST-related disputes, inaccuracies, and additional charges while improving overall accountability in tax reporting.

Conclusion

The intersection of generative AI and copyright law represents one of the most consequential intellectual property challenges of the twenty-first century. India's Copyright Act, 1957, particularly Section 2(d)(vi), offers a partial statutory foundation for addressing computer-generated works, but its drafting history and interpretive limitations make it inadequate to the task of regulating autonomous AI creativity at scale.

A coherent legal response requires, at minimum, legislative clarification on the authorship and ownership of AI-generated works, regulatory guidance from the Copyright Office of India on registration practices, and a considered position on the permissibility of training generative AI systems on copyrighted content. A sui generis protection regime distinct from traditional copyright but affording limited, purpose-specific protection to AI-generated content may offer a pragmatic intermediate solution that balances incentives for AI innovation with the imperatives of protecting human creative industries.

Until such reforms are enacted, practitioners, businesses, and creators must navigate an uncertain landscape with caution, relying on contractual mechanisms and careful documentation of human creative contribution to AI-assisted works.

Author: Aastha Singh in case of any queries please contact/write back to us via email to content@khuranaandkhurana.com or at  Khurana & Khurana, Advocates and IP Attorney

Endnotes

1. Central Goods and Services Tax Act, 2017, No. 12 of 2017, §§ 2(119), 13, 15, 31 (India).

2. Central Goods and Services Tax Act, 2017, Schedule II, Entry 6(a): Works contracts in respect of immovable property to be deemed as supply of service.

3. Central Board of Indirect Taxes and Customs (CBIC), GST Flyer on Works Contract, Government of India.

4. Goods and Services Tax Council, Advance Ruling in S.P. Singla Constructions Pvt. Ltd., Gujarat Appellate Authority for Advance Ruling (AAAR) on taxability of mobilisation advance.

5. Sankaranarayana Constructions Pvt. Ltd. Vs. Commissioner of Central Tax, Customs, Excise and Service Tax Appellate Tribunal (CESTAT) on applicability of time of supply to advances in construction contracts.

6. Dholera Industrial City Development Ltd., Advance Ruling Authority (Gujarat) on distinction between the consideration for contract and compensatory payment due to obligations in respect of projects.

7. Central Goods and Services Tax Rules, 2017: Tax invoice, receipt voucher, continuous supply of service and other related provisions.

8. CBIC circulars and notifications on works contracts, valuation and other related issues in GST.

9. ICAI Background Material on GST and Works Contracts, Institute of Chartered Accountants of India.