Dear Clients and Partners,
As we navigate the second quarter of 2026, businesses across Vietnam are finding themselves at a critical crossroads regarding tax compliance. With the full implementation of Circular 20/2026/TT-BTC, the landscape for deductible expenses has shifted significantly. While these regulations were designed to streamline reporting and modernize the tax system, they have also introduced a new layer of complexity that many enterprises are struggling to master.
Tax deductions are a powerful tool for optimizing your bottom line, but they are also one of the most scrutinized areas during a tax audit. In the current regulatory environment, the General Department of Taxation (GDT) has deployed sophisticated AI-driven auditing tools that can flag inconsistencies in real-time. If your business is still relying on outdated deduction strategies, you may be inadvertently inviting unnecessary risk.
In this comprehensive guide, we will explore the most common tax deduction mistakes currently being made under Circular 20/2026 and provide actionable insights on how to ensure your business remains compliant while maximizing its tax efficiency.
1. The Documentation Gap: Failing the "E-Invoice Only" Standard
One of the most significant changes introduced by recent regulations, and reinforced by Circular 20/2026, is the absolute necessity of valid electronic invoices (E-invoices) for all deductible expenses. Gone are the days when a simple paper receipt or a manual ledger entry would suffice during an audit.
The Mistake:
Many businesses continue to claim deductions for "legitimate" business expenses that lack a corresponding, verified E-invoice in the national system. Whether it is a small vendor who has not yet transitioned to the digital system or an internal oversight where the invoice was not properly archived, missing this documentation is an automatic disqualifier for a Corporate Income Tax (CIT) deduction.
How to Optimize:
- Validate in Real-Time: Implement a system where every vendor’s E-invoice is validated against the GDT portal immediately upon receipt.
- Digital Archiving: Circular 20/2026 requires that digital records be accessible for a minimum of ten years. Ensure your legal document management is robust and redundant.
2. Misclassifying Employee Benefits and "Work-from-Home" Allowances
With the rise of hybrid work models in 2026, the lines between personal and professional expenses have blurred. Circular 20/2026 provides specific guidance on what constitutes a "reasonable" employee benefit, yet many businesses are still misclassifying these costs.
The Mistake:
A frequent error involves claiming deductions for home office setups or internet allowances without a clearly defined internal labor policy or collective labor agreement. If these perks are not explicitly stated in your labor contracts, the tax authorities may view them as taxable income for the employee or non-deductible "welfare" expenses for the company.
The Solution:
To ensure these expenses are deductible, your business must:
- Include specific allowance clauses in all employment contracts.
- Ensure the total "welfare" expense does not exceed the cap of one month's average salary as prescribed by CIT law.
- Maintain clear evidence that the expense was directly related to business operations (e.g., dedicated hardware for remote servers).
3. Improper Amortization of "Intangible Assets"
As Vietnam’s tech sector matures, more companies are investing heavily in software, patents, and proprietary workflows. Circular 20/2026 has updated the depreciation and amortization schedules for these intangible assets, but many finance teams are still using outdated 2022-2024 cycles.
The Mistake:
Claiming a 100% deduction in a single year for significant software upgrades or intellectual property acquisitions is a common pitfall. Unless the asset meets the "small tool/equipment" threshold, it must be amortized over its useful life. Furthermore, if you are involved in M&A activities, the valuation of these assets must be strictly documented to avoid "over-deduction" penalties.
The Pro-Tip:
Consult with a highly qualified legal team to determine the exact amortization window for your specific industry assets under the new 2026 guidelines. Over-accelerating depreciation might look good for this year's cash flow, but it will lead to heavy fines and back-taxes during your next five-year audit.
4. The "Reasonable and Necessary" Trap for Business Travel and Meals
Business entertainment and travel have always been high-risk areas. However, Circular 20/2026 has introduced a "purpose-linkage" requirement that is much stricter than previous years.
The Mistake:
Claiming deductions for "business meals" that lack a participant list, a clear business agenda, or a direct link to a revenue-generating project. Similarly, travel expenses for "consultants" or "partners" that are not supported by formal service agreements or invitation letters are being flagged at record rates.
Strategy for Compliance:
- The Three-Way Match: Every travel or meal expense should be matched with (1) a valid E-invoice, (2) an internal approval memo stating the business purpose, and (3) evidence of the meeting (such as an email follow-up or a signed contract).
- Service Agreements: For external partners, ensure a formal contract is in place before the expenses are incurred.
5. Overlooking the "Non-Cash Payment" Rule for High-Value Transactions
This is perhaps the most "preventable" mistake on this list, yet it continues to occur in both SME and large enterprise sectors.
The Mistake:
Under current tax laws, any invoice with a total value of 20 million VND or more (including VAT) must be paid via non-cash methods (bank transfer) to be eligible for a CIT deduction. Circular 20/2026 has expanded the audit scope to include "split invoices": where a business breaks a 40 million VND purchase into two 20 million VND cash payments to circumvent the rule.
The Risk:
The GDT’s AI tools are now designed to aggregate payments to the same tax code (MST) over a 24-hour period. If the total exceeds the threshold and was paid in cash, the deduction will be disallowed entirely, and your VAT input credit will be rejected.
6. Incorrect Handling of Foreign Contractor Tax (FCT) Deductions
For companies utilizing international SaaS platforms, foreign marketing agencies, or overseas technical support, the Foreign Contractor Tax remains a complex hurdle.
The Mistake:
Many businesses pay the full invoice amount to an overseas provider but forget to withhold, declare, and pay the FCT on behalf of the contractor. Under Circular 20/2026, if the FCT has not been paid and settled with the tax office, the entire expense paid to the foreign entity is deemed non-deductible for CIT purposes.
Professional Guidance:
If your business relies on global talent or digital infrastructure, ensure your accounting department is performing monthly FCT reconciliations. Failing to do so doesn't just lose you a deduction; it results in late payment interest and potential "non-compliance" flagging.
Why Circular 20/2026 Demands Proactive Action
The transition to Circular 20/2026 represents a shift from "reactive" to "proactive" tax management. The Vietnamese government is increasingly focused on transparency and the digital economy. By understanding these common mistakes, you can optimize your tax position and streamline your path through future audits.
At BLaw Vietnam, we are thrilled to help our clients navigate these technical waters. Our team of experts specializes in identifying these subtle compliance gaps before they become costly liabilities. Whether you are looking to audit your current tax strategy or require assistance with licensing and regulatory compliance, we are here to ensure your business remains resilient and cost-effective.
Conclusion
Avoiding tax deduction mistakes is not just about saving money: it is about protecting the reputation and longevity of your business. Through the above article, it is clear that the requirements for documentation, categorization, and payment methods have reached a new level of stringency.
In addition to internal reviews, we highly recommend a periodic "Health Check" of your tax and labor records. A proven track record of compliance is your best defense against the uncertainties of a changing regulatory environment.
Are you ready to enhance your tax compliance and secure your deductions for the 2026 fiscal year?
We invite you to reach out to our team of professionals for a consultation. Let us help you turn complex regulations into a strategic advantage for your business.
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