Tata Consultancy Services announced a Rs 16,000-crore ($2.39-billion) share buyback, sparking a 4% surge in the stock price and intensifying pressure on rivals to follow suit as investors clamour for returns amid slowing growth.India's biggest IT services company said it will buy back 56 million equity shares, about 3% of total equity , at `2,850 apiece, a 14% premium to the stock's `2,506.5 close on Monday on the BSE.TCS had announced last week that the board would meet on Monday to consider the plan.“The buyback is proposed to be made from the shareholders of the company on a proportionate basis under the tender offer route,“ TCS said in an exchange filing.The move by the Mumbai-headquartered company comes less than two weeks after rival Cogni zant said it would return $3.4 billion to shareholders -in dividends and increased buybacks -after activist hedge fund Elliott Management questioned the company's capi tal-allocation policy.