HDFC Bank shares declined 3 percent on Friday amid reports that markets regulator SEBI is reviewing the resignation letter of former part-time chairman Atanu Chakraborty.

The stock fell after consecutive sessions of gains. It touched an intraday low of Rs 759.25 per share on the NSE, down 2.95 percent.

The decline follows reports that the Securities and Exchange Board of India (SEBI) has initiated a preliminary review of Chakraborty’s resignation letter for possible violations of rules governing directors of listed companies, according to sources.

Chakraborty told Reuters he was not aware of any such examination by the regulator.

In his resignation letter, Chakraborty referred to "certain happenings and practices within the bank" which he said were "not in congruence" with his personal values and ethics. He did not elaborate.

Meanwhile, global brokerage Jefferies also exited its holdings in shares of private lender HDFC Bank, while trimming its India weightage, shortly after part-time chairman and independent director Atanu Chakraborty resigned from the board.

The stock had fallen 8.7 percent in the following session after the letter surfaced, eroding about Rs 1.35 lakh crore in market capitalisation over three sessions.

Reuters sources said a SEBI department overseeing corporate disclosures and governance is examining the role of the former chairman and other directors for alleged lapses in fiduciary duties.

"The examination is to verify claims made in the resignation letter and whether other directors were aware of any material information and did not document them," Reuters reported citing sources.

HDFC Bank earlier said it has appointed external law firms to independently assess the concerns raised in the resignation letter. Chakraborty, however, told Reuters that the firms had not contacted him.