Ratan Tata, who led the transformation of the Tata group from a conventional corporate house into a $ 100 billion global conglomerate with high-profile acquisitions abroad, will retire on Friday ending 50-year run in one of India's oldest business empires.

Marking a generational change, Tata, who turns 75 on Friday, will hand over the reins of the group to 44-year-old Cyrus Mistry, who was chosen his successor in 2011 and formally appointed Chairman earlier in December.

Tata is hanging up his boots after steering the group for 21 years as its Chairman, when he succeeded the legendary JRD Tata. While JRD made Tata the Chairman out of the blue in 1991 RPT 1991, Mistry of the Shapoorji Pallonji group and whose family owns 18 per cent stake in Tata Sons, was chosen by a five-member selection committee.

When he took over in 1991 the group just had a revenue of about 14,000 crore, today its revenue is over 4,75,000 crore. Ratan Tata was born as Ratan Naval Tata in December 1937 and is the adopted great-grandson of Tata group founder Jamshedji Tata.

He was the force behind the acquisition of global brands like Tetly, the Anglo-Dutch steel maker Corus and Jaguar-Rover. His vision to transform the group into a multinational giant resulted in high profile acquisitions such as Tata Tea's takeover of UK brand Tetley for $ 450 million in 2000. (PTI)