The Reserve Bank of India has restricted how long a bank’s founder can stay on as chief executive officer, a move that will come as a blow to the world’s wealthiest banker.

Founder-CEOs can serve for 12 years, or 15 at the discretion of the regulator, the RBI said in a statement Monday. Lenders have until Oct. 1 to comply.

The new rules will directly impact Uday Kotak, CEO and founder of Mumbai-based Kotak Mahindra Bank Ltd., who has a net worth of $14.2 billion, according to the Bloomberg Billionaires Index. Kotak set up an investment company in 1985, which converted into a lender in 2003 and Kotak has led the bank since the beginning.

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Representatives for Kotak Mahindra Bank didn’t immediately respond to emails and calls for comment.