Short answer: When RSUs vest, the employer deducts TDS on the perquisite — but that TDS is based on the employer's estimate of your annual income, and a large mid-year vest can push you into a higher slab than the employer's calculation assumed. If your total tax liability after TDS credit exceeds ₹10,000 (s.208 ITA 1961), you must pay advance tax on the shortfall. The formula: (salary + perquisite + other income) × effective rate − employer TDS = advance tax payable, due by the instalment dates (last instalment 15 March). If total advance tax paid is below 90% of the assessed tax, interest under s.234B runs at 1% per month.

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Why employer TDS falls short

Employer TDS under s.192 is computed on estimated annual salary including expected perquisites. It can be understated when:

An RSU vests mid-year and the employer's year-start estimate did not include it;
The vest pushes you into a higher slab or triggers surcharge on a higher total income;
You have other income (capital gains, interest, a side business) outside the employer's payroll;
You work for a foreign employer with no Indian TDS at all.

The perquisite may look fully taxed (Form 26AS shows a TDS entry) while the total tax on your combined income is still uncovered.

The computation, step by step

Total income = salary + RSU perquisite (FMV at vest) + any other income.
Total tax = tax on total income at your slab (old or new regime, with surcharge/cess).
Less employer TDS (from Form 26AS) and any other TDS/prepaid tax.
Advance tax payable = balance, if it exceeds ₹10,000.
Pay by the cumulative instalments — 15 June (15%), 15 Sep (45%), 15 Dec (75%), 15 Mar (100%).

Worked example: Aisha's December vest

Persona: Aisha, salaried, FY 2025-26 (new regime, default). Salary ₹25,00,000; employer TDS on salary ₹2,40,000. On 15 December, 100 RSUs vest with FMV at vest ₹8,000 per share → perquisite ₹8,00,000. No other income.

Step 1 — Total income: ₹25,00,000 + ₹8,00,000 = ₹33,00,000.

Step 2 — New-regime tax (after standard deduction ₹75,000 → taxable ₹32,25,000):

0–4L: nil; 4–8L: ₹20,000; 8–12L: ₹40,000; 12–16L: ₹60,000; 16–20L: ₹80,000; 20–24L: ₹1,00,000; 24–32.25L @30%: ₹2,47,500

Total: ₹5,47,500 + 4% cess ≈ ₹5,69,400

Step 3 — Advance tax payable: ₹5,69,400 − ₹2,40,000 (TDS) = ₹3,29,400.

Step 4 — Pay: the vest happened in December, so the December and March instalments are the practical targets. If Aisha pays the full balance by 15 March, her s.234C exposure is limited to the early-instalment shortfalls judged against what was estimable then. s.234B applies where the advance tax paid by 31 March is less than 90% of the assessed tax (i.e., 90% of ₹5,69,400 ≈ ₹5,12,460 — not 90% of the ₹3,29,400 shortfall) — interest then accrues at 1% per month from 1 April on the full unpaid gap (assessed tax minus advance tax paid), until payment.

The trap: Aisha assumed the employer's ₹2,40,000 TDS "covered everything." It covered only salary; the ₹3,29,400 on the combined income was never withheld, and without advance tax she faces a ₹3.29 lakh bill plus interest at filing.

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Instalment planning around a mid-year vest

The instalment schedule is cumulative: 15 June (15%), 15 Sep (45%), 15 Dec (75%), 15 Mar (100%). The key protection for a mid-year vest: s.234C interest is judged on what was estimable at each instalment date. A vest that happens in December was not estimable in June, so the June and September shortfalls are generally not penalised. The practical plan:

Before 15 December, re-estimate total income including the vest and bring the paid-to-date position to at least 75% of the revised advance tax;
Before 15 March, pay the balance to 100%.

If the vest lands between 1 January and 31 March, the only instalment in play is the March one — pay the full shortfall by 15 March to avoid s.234C entirely on that amount.

Self-assessment at filing if you missed the dates

If you missed 15 March, you still owe the tax. Pay it as self-assessment tax (s.140A) before filing the ITR. The interest picture:

s.234C: 1% per month on the 15 March cumulative shortfall — for salary/non-business taxpayers this is typically 3 months' interest on the unpaid slice unless a narrower proviso applies;
s.234B: if total advance tax paid is below 90% of the assessed tax, 1% per month from 1 April on the shortfall.

Paying late is never cheaper than paying on time. Self-assessment tax before filing under s.140A only caps further accrual of s.234B — interest already accrued from 1 April to the payment date is still charged in the return. Paying at filing beats waiting for a demand (which adds s.220(2) interest on top) but does not erase the earlier months of s.234B.

The ₹10,000 threshold, restated

Advance tax is due only when the liability after TDS credit exceeds ₹10,000 (s.208). A small vest that leaves the balance under ₹10,000 triggers no advance-tax obligation — but the same ₹10,000 threshold applies to the total income position, so a salary-only TDS shortfall plus a modest vest can cross it even when the vest alone would not.

Frequently Asked Questions

1. Does employer TDS on RSU vest fully settle my tax?

Not always. The TDS covers the perquisite as the employer estimated it. If the vest pushes you into a higher slab, or you have other income, the total tax can exceed the TDS — the balance is advance tax.

2. When is advance tax on RSU income due?

By the cumulative instalments: 15 June, 15 Sep, 15 Dec, 15 Mar (15%/45%/75%/100%). For a mid-year vest, the December and March instalments are the practical deadlines.

3. What is the 90% rule?

If total advance tax paid is below 90% of the assessed tax, interest under s.234B at 1% per month runs from 1 April of the assessment year on the shortfall.

4. My employer is a foreign company with no Indian TDS. What do I do?

You are responsible for the tax yourself: declare the perquisite as salary in the ITR, compute the tax, and pay advance tax (and claim any foreign tax credit via Form 67). Do not assume the absence of TDS means the income is tax-free.

5. Can I pay advance tax only on the RSU portion?

You pay advance tax on the total uncovered liability (the balance after all TDS). There is no separate RSU-only instalment; the computation covers your total income.

6. What if I miss the March 15 deadline?

The shortfall attracts s.234C interest (1% per month on the 15 March cumulative shortfall — for salary/non-business taxpayers this is typically 3 months' interest on the unpaid slice unless a narrower proviso applies) and, if below 90% of assessed tax, s.234B from 1 April. Paying at filing via self-assessment tax still beats not paying at all.

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Compute your shortfall before 15 March

Use the Advance Tax Calculator — enter salary, TDS (from Form 26AS), the RSU perquisite, and other income. It computes total tax, the shortfall, the instalments, and the s.234B/234C exposure if you are late.

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Last verified: 2026-08-08.
Sources: Sections 192, 208, 211, 234B, 234C ITA 1961; Finance (No. 2) Act, 2024 (new-regime slabs, FY 2025-26).
Reviewer: pending CA sign-off. Draft status — do not publish before CA review.

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Advance Tax on RSU Vest: When Employer TDS Is Not Enough for High CTC Bands