What a Newly Established Enterprise Needs to Do on Tax and Accounting

Obtaining the Enterprise Registration Certificate is only the first step. From that day, the enterprise is a taxpayer and an accounting unit, even if it has not yet made a single sale.

Short conclusion: in the first 90 days, the enterprise needs to complete five groups of tasks — capital contribution, electronic tools (digital signature, tax account, e-invoices), accounting organization, tax filing periods and labor records. Doing them in the right order from the start keeps the books tidy, tax filing regular and avoids later corrections.

Where does a new enterprise get its tax code?

The enterprise does not need to apply for a separate tax code. The enterprise code recorded on the Enterprise Registration Certificate is also the tax code (clause 1, Article 29 of the 2020 Law on Enterprises).

The tax registration procedure accompanies enterprise registration through an interconnected mechanism. Current tax registration regulations are in Circular No. 90/2026/TT-BTC, effective from 1 July 2026. What to do right away is to check the information on the electronic tax portal: name, address, representative, managing tax authority.

What to do in the first 90 days, in order

The table below arranges the tasks in the order they should be done. This is a practical list, not a complete legal catalog; each enterprise needs to cross-check by business line and scale.

Capital contribution: why is it the first accounting task?

The charter capital recorded on the certificate is the figure the enterprise commits to. Members, owners and shareholders must contribute in full and in the right type of assets within 90 days from the date the Certificate is issued, not counting the time for transporting or importing the contributed assets or carrying out procedures to transfer ownership (clause 2, Article 47 of the Law on Enterprises for limited liability companies with two or more members; clause 2, Article 75 for single-member limited liability companies; clause 1, Article 113 for joint-stock companies).

Contributing through the enterprise’s bank account gives clear documents. If capital is not contributed in full on time, the company must register an adjustment of charter capital to the amount actually contributed (for example clause 4, Article 47 of the Law on Enterprises for limited liability companies with two or more members). This should be planned in advance, because contributed capital affects both the books and the rights of members.

E-invoices: register before selling

From 1 July 2026, e-invoices and e-documents are governed by Decree No. 254/2026/NĐ-CP, replacing Decree No. 123/2020/NĐ-CP and repealing Decree No. 70/2025/NĐ-CP. A new enterprise needs to choose an e-invoice service provider, register for use with the tax authority and wait to be accepted before issuing the first invoice.

Two points where new enterprises often get confused:

• When to issue an invoice. Each type of transaction (sale of goods, services, services with reconciliation) has a different issuance time. The process between the sales department and accounting should be agreed from the start.
• Input invoices. For an expense to be counted at finalization, valid invoices and documents are needed, with payment made as regulated. A good habit of retaining documents from the first month reduces year-end supplementation.

Accounting regime and the accounting person in charge

Choosing the accounting regime. Small and medium enterprises may continue to apply Circular No. 133/2016/TT-BTC, or choose Circular No. 99/2025/TT-BTC — the enterprise accounting regime applicable from financial years beginning on or after 1 January 2026. Choose once from the start and apply it consistently throughout the financial year.

Who does the accounting. Under Article 20 of Decree No. 174/2016/NĐ-CP:

• A micro-enterprise may arrange a person in charge of accounting and is not required to arrange a chief accountant (point b, clause 2).
• Other enterprises that cannot appoint a chief accountant immediately arrange a person in charge of accounting or hire a service to act as chief accountant; the period of arranging a person in charge of accounting is at most 12 months (clause 1).

The enterprise may recruit its own accountant or hire an accounting service business. What matters is having a person clearly responsible for the books and the filing deadlines.

Tax filing period: monthly or quarterly?

From 1 July 2026, tax filing is carried out under Law on Tax Administration No. 108/2025/QH15, Decree No. 252/2026/NĐ-CP and Circular No. 89/2026/TT-BTC.

The enterprise determines its own filing period. Even when no revenue has arisen, a return still needs to be filed in the right period.

Incentives for small and medium enterprises. Clause 4, Article 10 of Resolution No. 198/2025/QH15 exempts small and medium enterprises from CIT for 03 years from the date the Enterprise Registration Certificate is first issued. Decree No. 20/2026/NĐ-CP guides the conditions and the cases where it does not apply. It must be checked against the specific dossier (representative, owners, origin of establishment) before applying.

Labor and social insurance from the very first employee

When recruiting employees who fall under compulsory social insurance, the employer must declare and file the participation dossier within 30 days from the date the employee becomes subject to participation (clause 1, Article 28 of Law on Social Insurance No. 41/2024/QH15).

Salary, labor contracts, social insurance and related PIT are closely linked. An enterprise expecting to recruit many people should build the labor records process from the start. See also: Labor and Social Insurance Records for Enterprises with Many Employees.

Where new enterprises often get stuck and how to handle it

• Leaving first-month documents scattered. When it easily happens: the owner spends on their own and has no accounting person in charge yet. How to handle: set up a monthly documents folder from the start, agree who keeps and who approves.
• Forgetting to file the return because of “no revenue yet”. How to handle: set a calendar of deadlines by the chosen period, and assign one person to track it.
• Capital not fully contributed when 90 days end. How to handle: review the capital actually contributed before the 90-day milestone to decide whether to contribute more or register an adjustment of capital.
• Applying a tax incentive without checking the conditions. How to handle: cross-check the conditions in Decree No. 20/2026/NĐ-CP before finalization.

How Thái Tín helps

Thái Tín takes in the new enterprise’s information, works with the owner to draw up a list of tax, accounting and labor tasks by milestone, and connects suitable accounting units and tax agents to carry out the professional work: bookkeeping, preparing returns, financial statements, finalization. Thái Tín coordinates and tracks progress within the agreed scope; enterprises with large workforces or foreign capital are advised according to their own particulars.

Costs include the service fee of the implementing unit and tool costs (digital signature, e-invoices) if any; a quote is given after seeing the scale and volume of documents. If the enterprise is at the stage of preparing to be established, read also Setting Up a Company: What to Prepare – Type, Capital, Business Lines or see the services across the enterprise life cycle.

Keeping tax and accounting steady from the first year

• One shared calendar. Note the milestones: 90 days for capital contribution, quarterly return deadlines, annual finalization deadline, 30 days to register social insurance for new employees.
• One person responsible. Whether done in-house or outsourced, a single point of contact should hold the books and the filing deadlines.
• End-of-quarter review. Cross-check invoices, bank statements and the payroll before filing the return.
• Follow new regulations. In 2026 there are many new tax and invoice documents; re-check when preparing dossiers.

To find out what your enterprise is still missing, send your enterprise registration information and current status to get a list of tasks to do.

Questions and answers

Related articles

Company Setup Setting Up a Company: What to Prepare – Type, Capital, Business Lines Labor & Social Insurance Labor and Social Insurance Records for Enterprises with Many Employees Company Setup Foreign-Invested Company Setup: Steps Under the 2025 Law on Investment