The bank is expected to raise up to USD 1 billion from these dollar-denominated bonds.

''We hereby inform you that the bank had approved the issuing of debt instruments in the form of the notes, subject to market conditions,'' HDFC Bank said in a regulatory filing.

An offering memorandum (OM) has been prepared and shall be made available to the prospective investors in relation to the contemplated issue of notes, it said.

The notes will not be offered or sold in India under the applicable laws, including the Companies Act, 2013, as amended from time to time, it added. Earlier in April, the bank had informed that it is planning to raise up to Rs 50,000 crore during the next 12 months through issuing bonds.

''The bank proposes to raise funds by issuing perpetual debt instruments (part of additional tier-I capital), tier-II capital bonds, and long-term bonds (financing of infrastructure and affordable housing) up to a total amount of Rs 50,000 crore over the period of the next 12 months through the private placement mode,'' HDFC Bank had said.

Perpetual bonds carry no maturity date, so they may be treated as equity, not as debt.