Section 20 deals with the distribution of Input Tax Credit (ITC) of input services received at a Head Office or centralized office to its branches having the same PAN through the Input Service Distributor (ISD) mechanism. The provision was significantly updated from 1 April 2025, making ISD registration mandatory in specified cases.

What is an ISD?

An Input Service Distributor (ISD) is an office that receives invoices for common input services used by multiple branches and distributes the related ITC to those branches.

Example

Head Office (Mumbai) receives an audit fee invoice:

• Audit Fee = ₹1,00,000
• GST = ₹18,000

The audit relates to:

• Gujarat Branch
• Rajasthan Branch
• Maharashtra Branch

Since all branches benefit from the service, the Head Office distributes the ITC of ₹18,000 to the concerned branches through the ISD mechanism.

Key Principles of Section 20

1. ITC Cannot Exceed Available Credit

The ISD cannot distribute more credit than what is available in its electronic credit pool.

2. Specific Credit Goes to Specific Branch

If an input service exclusively relates to one branch, the entire ITC must be distributed only to that branch.

Example

Legal fee relates only to the Jaipur branch.

GST on legal fee = ₹9,000

Entire ₹9,000 ITC will be distributed only to Jaipur branch.

3. Common Credit Distributed on Turnover Basis

Where services are used by multiple branches, ITC is distributed in proportion to their turnover.

Example

Common Advertisement Service

GST Credit = ₹30,000

Distribution:

• Gujarat = ₹18,000
• Rajasthan = ₹9,000
• Maharashtra = ₹3,000

Documents Required

The ISD distributes credit through an ISD Invoice / ISD Credit Note containing prescribed details.

Practical CA Example

A company has:

• HO in Mumbai
• Factory in Ahmedabad
• Depot in Jaipur

HO receives:

• Audit Fees
• ERP Software Charges
• Consultancy Fees

These services benefit all locations.

Instead of keeping ITC at HO, Section 20 allows the HO (as ISD) to distribute ITC to Ahmedabad and Jaipur based on turnover.

Quick Summary Table

Practical Importance

Section 20 is mainly relevant for:

• Companies having multiple GST registrations under the same PAN
• HO incurring common expenses
• Shared services such as audit, legal, software, consultancy, advertisement, HR, ERP, etc.

Easy Memory Trick

Section 18 = Special ITC
Section 19 = ITC on Job Work
Section 20 = Distribution of ITC through ISD
Section 21 = Recovery of Excess ITC Distributed

In simple terms: Section 20 answers the question, "How will a Head Office distribute common service GST credit to its branches?" through the Input Service Distributor (ISD) mechanism.