A Chinese specialist assigned to a battery or EV project in Vietnam — paid partly in China, partly in Vietnam — how is personal income tax (PIT) computed, where is it paid, and can the Vietnam–China treaty reduce it? The answer hinges on a single milestone: whether the individual is a Vietnamese tax resident (present 183 days or more in a calendar year). Resident: taxed on worldwide income at progressive rates (5%–35%), including the China-paid salary portion. Non-resident: taxed only on Vietnam-source income at a flat 20%. This article explains how to determine residence, how to file split payroll, and how to apply Article 15 of the treaty to avoid double taxation.
Step 1: Determine resident vs non-resident status
The 183-day test
Under the PIT Law and Circular 111/2013/TT-BTC, an individual is resident in Vietnam by meeting any of: presence in Vietnam for 183 days or more in a calendar year (arrival and departure days each count as one), or having a regular residence in Vietnam. For Chinese specialists rotating through battery/EV projects, day-counting must be exact — passport entry/exit stamps are the evidence. A frequent error: companies assume the specialist “will surely stay under 183 days” without tracking, then discover the breach at year-end when the whole tax plan collapses and amended filings are due.
Tax consequences of each status
Resident individuals: PIT on worldwide income — including the salary portion paid by the Chinese parent in China for work performed in Vietnam. Tax follows the progressive scale in seven brackets (5% to 35%), with family deductions allowed. Non-resident individuals: tax only on employment income arising in Vietnam, at a flat 20% on gross income (no family deductions, no progression). At high specialist salary levels, flat 20% is sometimes “cheaper” than progressive rates — but status is not a planning election: residence is an objective fact, not a tax optimisation choice.
Step 2: Handling “two-pocket” Vietnam–China payroll
The common model: the specialist draws part of the salary from the Vietnamese company (a Vietnam cost) and part from the Chinese parent (preserving Chinese benefits and insurance). Under Vietnamese tax principles: all income from work performed in Vietnam — wherever and in whatever currency paid — falls within Vietnam’s tax net (worldwide for residents; Vietnam-source portion for non-residents). The Vietnamese enterprise must withhold, declare and remit PIT on the portion it pays; for the parent-paid portion, the specialist (or an authorised agent) must self-declare in Vietnam. Inspection reality: tax authorities cross-check declared total income against multiple data sources — under-declaring the “China-pocket” salary is a common violation that gets reassessed.
Step 3: Applying Article 15 of the double tax agreement
If the specialist is also a Chinese tax resident and meets all three conditions of Article 15 of the Vietnam–China treaty (presence not exceeding 183 days in any 12-month period; remuneration paid by a non-Vietnamese-resident employer; remuneration not borne by a Vietnamese permanent establishment), the salary is taxable only in China. To secure exemption in Vietnam, file the treaty application (with the Chinese Tax Residency Certificate) with the Vietnamese tax authorities. Watch out: the third condition — “not borne by a permanent establishment in Vietnam” — is usually the breaking point: if the salary cost is booked into the Vietnamese company (even if the Chinese parent merely reimburses it), the authorities may treat it as borne locally, and the taxing right stays with Vietnam.
Putting it together: a worked planning sequence
Consider a typical 14-month assignment straddling two calendar years. First, map the physical presence month by month against both the calendar-year residence test and the rolling 12-month treaty test — they are different clocks, and breaching either changes the outcome. Second, decide the payroll split deliberately: salary booked in Vietnam creates a local deduction for the company but strengthens the “borne by” argument against treaty relief; salary kept in China preserves the treaty position but is non-deductible locally and still declarable by the individual. Third, align the secondment agreement with the tax position: which entity is the legal employer, who bears the cost, and how recharges are documented determines both the Article 15 analysis and the transfer-pricing treatment of any cross-charge. Fourth, calendar the compliance: monthly withholding on the Vietnam-paid portion, quarterly provisional filings where required, the treaty relief application with TRC, and the year-end finalisation. Fifth, do not forget social insurance: specialists working one year or more join compulsory SI under Decree 143/2018/ND-CP, and the employer’s SI cost belongs in the project’s total specialist-cost budget. Groups that run this five-step sequence for every inbound specialist avoid the classic year-end surprise; groups that improvise pay for it in reassessments and penalties.
The PIT finalisation calendar for Chinese specialists — never leave tax “debts”
Annual finalisation: who files, when?
Chinese specialists who are Vietnamese tax residents (present 183+ days/year or with a regular dwelling) must file annual PIT finalisation — monthly withholding by the company is not the final number. Classic trap: the specialist leaves before year-end — who finalises their income? Employment/secondment contracts must assign finalisation responsibility (company files for them, or the individual self-files); otherwise tax authorities will come to the company (the payer) for collection.
Dependants and deductions — don’t leave money behind
Chinese specialists with spouses/children in China may still register dependants in Vietnam if conditions are met (relationship proof, dependant income below thresholds). Reality: many companies skip registration because “Chinese documents are hard to translate” — each unregistered dependant forfeits a monthly deduction, compounding to large annual sums. Fix: on the specialist’s arrival, collect dependant files (birth certificates, marriage registration — translated and notarised) and register dependant tax codes.
Coordinating with Chinese taxation — avoiding double tax
Specialists may face Vietnamese PIT and Chinese tax on worldwide income (if still Chinese tax residents). The Vietnam–China DTA allocates taxing rights — but not automatically: a foreign tax credit claim must be filed in China. Prepare: keep Vietnamese tax payment evidence (monthly withholding receipts, annual finalisation confirmations) — the “ticket” for the Chinese credit claim.
The departure-year problem most companies mishandle
When a specialist leaves Vietnam mid-assignment, three things must happen in sequence: (1) a departure PIT finalisation covering the Vietnam-source income up to the departure date; (2) a tax-clearance confirmation for immigration/exit procedures where required; (3) handover of all tax documents to the individual (or their Chinese tax adviser) for the home-country filing. Companies that skip step 1 discover the liability years later during a tax audit — with penalties and interest. Build a departure checklist into HR offboarding: final payroll, final withholding, finalisation filing, document handover, all before the farewell dinner.
The mobile-expert problem — tracking across projects
Battery/EV Chinese experts typically rotate across projects (Vietnam – China – third countries) — every entry/exit affects residence-day counts. Recommendation: maintain a travel calendar per expert, reconciled quarterly — never count at year-end (without passports and tickets, nothing is provable).
Split payrolls — the common trap
Many experts are paid partly in China (home payroll) and partly in Vietnam (allowances) — Vietnamese tax applies to worldwide employment income once tax residence is established, regardless of where paid. The trap: declaring only the Vietnamese-paid portion — tax audits request home-country payroll records through information exchange (Vietnam–China tax cooperation). Fix: consolidate global employment income per expert before filing — and claim foreign tax credits (not exemptions) for Chinese-paid portions under the DTA. Documentation: keep both payrolls, both tax receipts, and the secondment agreement (who is the real employer? — it determines withholding duties).
PIT checklist for Chinese specialists
Before arrival: (1) plan the rotation and track actual presence days; (2) pre-determine the resident/non-resident scenario and payroll model; (3) prepare the employment/secondment contract recording the two-pocket salary structure. Monthly/quarterly: (4) withhold and declare PIT on the Vietnam-paid portion; (5) collect evidence of the China-paid portion for complete declaration. Year-end: (6) finalise PIT; (7) if claiming treaty relief, file the exemption application with TRC on time. Don’t forget: compulsory social insurance (Decree 143/2018/ND-CP) for specialists working one year or more — part of the project’s total specialist cost.
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This article has been quality-reviewed by the FLAW AI Legal Council