SBI TT Buy Rate for RSU Vesting — Rule 115 Explained

By GainSutra · Updated May 2026 · 7 min read

The single most common error in RSU tax filing in India is using the wrong SBI TT rate. Most people use either today's rate, the rate on the transaction date, or an average rate from the month. None of these is correct. Rule 115 of the Income Tax Rules 1962 is specific: use the SBI TT Buy rate on the last working day of the month immediately preceding the month of the transaction.

Rule 115(1) — the actual text: "The rate of exchange for the calculation of the value in rupees of any income accruing or arising or deemed to accrue or arise to the assessee in foreign currency or received or deemed to be received by him or on his behalf in foreign currency shall be the telegraphic transfer buying rate of such currency as on the specified date."

The rule fixes the rate source (SBI TT buying rate) and then defines the specified date separately for each head of income. For salary — which includes an RSU or ESOP perquisite — for dividends, and for capital gains, that specified date is the last day of the month immediately preceding the relevant month. That is the rule this page deals with. Note two carve-outs: ordinary foreign bank interest falls under other sources and takes the 31 March rate, and wherever tax was deducted at source the proviso overrides and the TDS date governs. Full breakdown by income head: Rule 115 explained.

What "Last Working Day of Preceding Month" Actually Means

If an RSU vests on March 15, 2025, the applicable rate is the SBI TT Buy rate on the last working day of February 2025. February 28, 2025 was a Friday and a working day — so the rate on February 28, 2025 is the correct rate.

If March 31 is a bank annual closing day (which it often is in India), and RSUs vest on April 5, 2025, the applicable rate is the last working day of March. Since March 31 may be a closing day, the rate from March 29 or March 30 would apply depending on which was the last working day.

Transaction date	Preceding month	Rate to use
March 15, 2025	February 2025	SBI TT Buy rate on Feb 28, 2025
July 6, 2025	June 2025	SBI TT Buy rate on Jun 30, 2025
January 31, 2026	December 2025	SBI TT Buy rate on Dec 31, 2025
April 1, 2026	March 2026	SBI TT Buy rate on last working day of March 2026

TT Buy vs TT Sell — Which One?

Use the TT Buy rate — not the TT Sell rate, not the Bill Buy rate, not the RBI reference rate. The SBI TT Buy rate is the rate at which SBI buys foreign currency from you. For income received in foreign currency (like RSU vest proceeds or dividends), this is the applicable rate.

The TT Buy rate sits below the TT Sell rate. Using TT Sell inflates every converted figure in the return — a conversion no rule supports, and one an assessing officer can check against SBI's published card in seconds.

Where to Find Official SBI TT Buy Rates

SBI publishes forex rates on its official website. The historical rates are available at sbi.co.in. For the purpose of RSU tax filing, you need the last working day rate for each month going back several years. GainSutra maintains an archive of month-end SBI TT Buy rates across USD, EUR, GBP and other major currencies, verified against official SBI publications. The month-end USD, EUR and GBP series is published free on our SBI TT rates page.

Caution: Many third-party finance sites show "SBI rates" that are derived from interbank or ECB mid-rates with an approximation factor. These do not match official SBI TT Buy rates and should not be used for tax filings.

Correct Rule 115 rates — automatically applied

GainSutra applies the correct SBI TT Buy rate for every transaction in your broker statement — last working day of the preceding month, per Rule 115, from a verified archive of official SBI rates.

Check Rates →

From FY 2026-27: Rule 115 Becomes Rule 206

The Income-tax Act, 2025 takes effect on 1 April 2026 and the Income-tax Rules, 2026 replace the 1962 Rules. The conversion provision is renumbered — Rule 115 becomes Rule 206, and the definition of "telegraphic transfer buying rate" moves from Rule 26 to Rule 207. The mechanism is unchanged: same SBI TT buying rate, same specified dates. Income of FY 2025-26 and earlier cites Rule 115; income of FY 2026-27 onward cites Rule 206. Your RSU working does not change, only the rule number you quote in it.

Frequently Asked Questions

Can I use the RBI reference rate instead of SBI TT Buy rate?

No. Rule 115 specifically requires the SBI TT Buy rate (telegraphic transfer buying rate). The RBI reference rate is a different rate and is not the rate prescribed under Rule 115.

Does this change under the Income-tax Act, 2025?

Only the numbering. From FY 2026-27 the provision is Rule 206 of the Income-tax Rules, 2026, with the TT buying rate defined in Rule 207. The rate source and the specified dates carry over unchanged.

What if SBI did not publish a rate on the last day of the month?

Use the rate from the last preceding date on which SBI actually published a TT buying rate, apply it consistently, and note in your working papers which date you used and why. Take care with Saturday cards: SBI often publishes a card quoting 0.00 against every currency because the forex desk is not dealing. A zero is not a rate — step back to the last card carrying real figures. There is no CBDT circular prescribing a fallback, so consistency plus documentation is your defence.