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 — the exact requirement: The rate of exchange for conversion of foreign currency into Indian currency shall be the telegraphic transfer buying rate of such currency as on the last day of the month immediately preceding the month in which the income is received or paid.

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 SBI TT Buy rate is always lower than the TT Sell rate and lower than the Bill Buy rate. Using the wrong rate type overstates income — which technically increases your tax liability, but misrepresents the actual conversion.

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 a database of SBI TT Buy rates from 2001 to present across USD, EUR, GBP, AUD, DKK and SGD — verified against official SBI publications.

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 database going back to 2001.

Check Rates →

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.

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

If the last day of the month is a Sunday or bank holiday, use the rate from the last day on which SBI published rates — typically the preceding Saturday or the Friday before a long weekend.