Kamath after he completed his 5-year term in the state-run bank on Monday.
As per the government rules, the CMD and Directors are appointed in public sector entities for a period of five years or up to the age of 60, whichever is earlier.
Following this shares of the bank opened on a weaker note and fell as much as 2.20 per cent to an intra day low of Rs 900.50. At the end of the trading session, the share was quoted at Rs 904.35, down 1.79 per cent over the previous closing price on the BSE.
Kamath, who joined PNB in October 2009, had another 13 months to superannuation.
Prior to joining PNB, he was the CMD of Allahabad Bank.