It said the 78-year-old Ratan Tata had been appointed interim chairman until a successor could be found.
Tata Sons took particular offence to Mistry's alleged departure of the group's value system and ethics, which it said was adhered to both in the boardroom and by its 600,000 plus employees.
Responding to Mistry, Tata Sons, in a statement, said "it will be beneath the dignity of Tata Sons to engage in a public spat with regard to the several unfounded allegations appearing in his leaked confidential statement".
Tata Sons made the point that Mistry was not new to the working of the group, nor to its culture and ways. "The Tata Sons board gives its Chairman complete autonomy to manage opportunities and challenges", said Tata Sons, the holding company for the $103 billion conglomerate. Though he was party to the decisions made in many capacities for over a decade, it is only after his removal that allegations and misrepresentation of facts are coming up.
Earlier in the day, the companies Mistry's email named as mired in losses defend themselves.
Inside Tata, a company that promotes its roots in the heritage and social values of the Parsi community, some workers have bristled at the board's treatment of Mistry.
Mistry's ouster has led to a bitter public feud between the former chairman and the Tata Sons with the former accusing the company of deep financial problems that Mistry inherited, and deep-seated differences over strategic direction of the company. But executives also questioned Mistry's efforts to restructure the group."It is like a bunch of finance or hedge fund guys that have walked in and made a decision to cut everything".
It is rumoured that one of the reason for the summary sacking of Mistry was his bid to sell the troubled Tata Steel UK, whose networth has completely eroded since the past few years. You can not defy your largest shareholder and hope to survive, that's the message that seems to have gone out from the trustees of the Sir Ratan Tata Trust and Sir Dorabji Tata Trust, headed by Ratan Tata as chairman. "The directors of the Tata Sons board had repeatedly raised queries and concerns on certain business issues, and trustees of the Tata Trusts were increasingly getting concerned with the growing trust deficit with Mistry, but these were not being addressed". It said that examples provided by Mistry were "selective" and "convenient" and did not represent the true state of affairs.
The Board of Directors of Tata Sons is composed of several eminent personalities from all walks of life.
Mistry also questioned the viability of Tata Motor's Nano project, which he said had lost around 10 billion rupees at its peak.
It is unfortunate that Mr. Mistry had overwhelmingly lost the confidence of the Members of the Board of Directors for a combination of several factors, it added. "This is not a group of people who one would expect to act without exercising proper judgment in the best interests of the entities they sit on the boards of".