Tata Sons will use the funds to pay creditors of its wireless division.
After this block deal, Tata Sons will hold about 73% in TCS, which generated $18 billion in revenues in fiscal 2017.
Data available from the NSE showed that the holding firm of the Tata group sold 2.06 crore shares of the country's largest IT services firm at a price of Rs 2,876.46 per share. Tata Sons also has to repay debt of around Rs 35,000 crore owed by Tata Teleservices, which is now expected to merge with Airtel, industry sources said.
Shares in Tata Consultancy Services fell 5.4 percent. They were down 5.1%, headed for the biggest one-day decline in more than three years, at 1:13 p.m.in Mumbai. The selling price range is a 4-6 per cent discount to TCS' Monday closing price of Rs3,052 on the BSE.More news: Oil prices fall on continued rise in crude output
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Some reports said Tata Sons may already have sold stake after markets opened on Tuesday, while others suggested that the sale took place on Monday evening. An official at Tata Sons declined to comment on the final pricing.
The conglomerate has been planning to raise its ownership over time in five of its largest businesses including Tata Chemicals and Tata Steel, Bloomberg News reported previous year. Last year, it boosted its stake in Tata Motors Ltd., the owner of Jaguar Land Rover.
Citigroup and Morgan Stanley are managing the TCS share sale. The latter had to shell out $1.2 billion to NTT DoCoMo previous year in order to settle the long-standing dispute with the Japanese telecom giant after it exited their joint venture in 2013.
Tata Sons is reportedly planning to use the proceeds to pay debts of units Tata Teleservices and Tata Teleservices Maharashtra.