By the time Ratan Tata took over in 1991, the group had already crossed $4 billion in annual revenues. In his last year of tenure in 2012, when Tata retired, this figure had crossed the $100-billion mark, making Tata Group the first Indian conglomerate to reach the target.

In March 1991, Ratan Tata was vice chairman of Tata Industries. He had entered Tata Industries as an assistant in 1962 and went on to become chairman as of March 1991. At that time, the group was a collection of semi-autonomous divisions under JRD Tata's decentralised leadership. Tata centralised management at Bombay House, the group's headquarters, and led the company through India's economic liberalisation in the early 1990s.

Under his leadership, Tata restructured the group by selling off underperforming sectors, which included cement, textiles, and pharmaceuticals. Strengthened these groups with software and steel and forayed into new ones like telecom, passenger cars, insurance, finance, retail, and aviation.

Besides domestic ventures, the company forayed into all-important international tie-ups with companies like Cummins, AIA, and Starbucks. The major acquisitions include Jaguar Land Rover, Tetley, and Corus. At the end of Tata's tenure, more than 60 percent of the group's revenue was generated from operations in more than 100 countries.

Ratan Tata changed the group's corporate governance by making the holding company, Tata Sons, take major stakes in the main units. Thus, hostile takeover was well excluded. He also gave three-dimensional, blue-colored logo to the brand that made the value of the brand increase from $300 million in 1998 to $11 billion in 2012.