MUMBAI (Reuters) - India's Tata Sons [TATAS.UL] is set to sell on Tuesday a roughly 1.5 percent stake in its flagship Tata Consultancy Services for about $1.25 billion (899.73 million pounds).

Tata Sons, which owned 73.5 percent of TCS as of end-December, is selling TCS shares in a price range of 2,872 rupees to 2,925 rupees each, according to a deal term sheet.

That would be a discount of 4.2 to 5.9 percent to TCS's Monday closing price of 3,052.15 rupees.

TCS, the top Indian software services exporter, is the second-most valuable company in the country with a market capitalisation of close to $90 billion.

Citigroup and Morgan Stanley are managing the TCS share sale.

($1 = 65.0050 Indian rupees)

(Reporting by Devidutta Tripathy, Euan Rocha and Fiona Lau of IFR; editing by Jason Neely)