On the Bombay Stock Exchange (BSE), Coffee Day Enterprises and SICAL Logistics shares fell by the daily maximum limit of 20 per cent each to Rs 123.25 and Rs 58.25 respectively.

Shares in Coffee Day Enterprises hit an all-time low on Wednesday, and were on course to end lower for a sixth session in a row. In the last six sessions the stock has slumped 38.34 per cent on the BSE.

Mr Siddhartha, the founder of the Cafe Coffee Day (CCD) chain, had not been reachable since late Monday, his flagship entity Coffee Day Enterprises said in a regulatory filing on Tuesday.

Coffee Day Enterprises has appointed Nitin Bagmane as interim chief operating officer and SV Ranganath as interim chairman, the company said in a regulatory filing after a board meeting on Wednesday.

"The Board took cognizance of statements in the purported letter from Mr VG Siddhartha relating to financial transactions outside the knowledge of the senior management, auditors and the Board. While the authenticity of the letter is unverified and it is unclear whether these statements pertain to the Company or the personal holdings of Mr VG Siddhartha, the Board took serious note of the same and resolved to thoroughly investigate this matter," Coffee Day Enterprises said.

Mr Siddhartha was the owner of cafe chain Cafe Coffee Day and also one of the promoters of SICAL Logistics. He owned a 32.75 per cent stake in Coffee Day Enterprises.

Together with his family and holding companies, he controlled 53.93 per cent of the firm.

Mr Siddhartha was recently in the news after he sold about 20 per cent of his stake in tech company Mindtree to engineering and construction company Larsen & Toubro.

Mr Siddhartha, whose Cafe Coffee Day chain has more than 1,600 stores across the country, was widely recognised for bringing the coffee shop culture to India more than 10 years before global coffee shop giant Starbucks Corp began its foray into the country.