The offer by CD&R, which currently owns about 49% of Cornerstone's common stock, represents a premium of about 34% to the stock's last close on Friday.

Shares of Cornerstone surged more than 25% to $23.08 in premarket trading. As of Friday's close, the company had a market value of about $2.32 billion, according to Refinitiv IBES data.

CD&R intends to remain a shareholder of Cornerstone if a potential deal cannot be completed under its proposal, the buyout firm said in an SEC filing, adding that it was not interested in pursuing any alternative transactions.

Bloomberg News first reported the news on Thursday.

(Reporting by Deborah Sophia in Bengaluru; Editing by Amy Caren Daniel)