Mumbai, Dec 28 (IANS) There was no event to mark the occasion, no speeches and the icon himself was not even there at Bombay House to see the transition, as Ratan Naval Tata Friday retired as chairman of the $100-billion Tata Group, after a 50-year association.

Cyrus Pallonji Mistry, 44, unanimously named a year ago as Tata's successor by the board of Tata Sons, the holding company, will take over the reins Saturday as the sixth chairman of the group, which was established in 1868 by Jamsetji Nusserwanji Tata.

Ratan Tata, who turned 75 Friday, will now be the group's chairman emeritus.

"He (Mistry) has been on the board of Tata Sons since August 2006 and I have been impressed with the quality and calibre of his participation, his astute observations and his humility," Tata had said of his successor, calling him intelligent and qualified.

At Tata Group headquarters Bombay House, scores of journalists, photographers and TV crew waited for Ratan Tata to arrive but were told that he was not in station. Mistry - whose sister is married to Noel Tata, Ratan Tata's half-brother - made a quiet entry.

In his farewell letter to all Tata Group employees, Rata Tata thanked them for their support extended during the last two decades when he was the chairman.

"This is also the last time that I write to you prior to my retirement as the chairman of the Tata Group and I want to convey to you how privileged I have been to have had the opportunity of leading this great group over the last two decades through good times and bad," Tata said.

Tata urged the employees to extend the same support to his successor, Cyrus Mistry.

"The future growth of the group will be led in the coming years by Cyrus Mistry. I am sure that he will receive from you the same support, the same commitment and the same understanding that I have enjoyed over the years," he said.

It will be a no mean task for Mistry, the youngest son of construction magnate Pallonji Mistry, whose family is the largest shareholders of Tata Sons with an 18.8 percent stake.

The Tata Group today has in its fold 100 companies, manufacturing from salt to steel and soap to cars, with a turnover of $100.09 billion -- close to 60 percent of which comes from overseas -- having operations in 80 countries and employing 450,000 people.

Mistry, who holds an M.Sc. in management from London Business School, will be the sixth chairman of Tata Group in its 144-year history and only the second who does not carry the "Tata" surname. Others besides Ratan Tata who held the position of chairman of the Tata Group are: Jamsetji Nusserwanji Tata, Sir Dorab Tata, Sir Nowroji Saklatwala and J.R.D. Tata.

"I take this responsibility very seriously and in keeping with the values and ethics of the Tata Group I will undertake to legally disassociate myself from the management of my family businesses to avoid any issue of conflict of interest," Mistry had said on his appointment as deputy chairman of Tata Sons last year.

Mistry had joined the board of his family-run firm Shapoorji Pallonji & Company in 1991 and was appointed managing director of the company 1994. Mistry left his family business last year in November upon his appointment as Ratan Tata's successor in Tata Sons, the holding company of salt-to-steel conglomerate Tata Group.