Boston-based Parexel had a market value of about $3.51 billion (2.71 billion pounds) as of Friday's close. The company's stock rose as much as 10.2 percent to $75.87 in morning trading.

The Wall Street Journal first reported about the talks, saying Parexel is working with investment bankers to sound out potential buyers, including private-equity firms, citing sources familiar with the matter.

The company did not immediately respond to a request for comment.

(Reporting by Carl O'Donnell in New York, additional reporting by Akankshita Mukhopadhyay in Bengaluru; Editing by Shounak Dasgupta)

By Carl O'Donnell