Mahindra Satyam saw 27.2 million shares, or about 2.31 per cent of its equity change hands, at 114.90 rupees a share on the BSE, stock exchange data showed on Friday.
An official at leading engineering and construction firm Larsen & Toubro, who did not want to be named, said the company was the seller.
A television channel had reported late on Thursday that Larsen & Toubro will raise $65 million by selling 27 million shares in Mahindra Satyam at 112.50 rupees on Friday.
Mumbai-based L&T owns 81 million shares in Mahindra Satyam, the channel said, adding the company had hired Nomura for the share sale.
Mahindra Satyam was formerly known as Satyam Computer Services, which was hit by India's biggest corporate fraud at the start of the year.
In April, L&T lost the race for control of the outsourcer to Tech Mahindra Ltd, a unit of Mahindra & Mahindra Ltd.
L&T had built up a 12 percent stake in Satyam, but the expansion of share capital because of the takeover meant it held 6.9 percent in Mahindra Satyam.
(Reporting by Ami Shah; Editing by Ramya Venugopal)