John Laing, originally into construction before moving to investing in and managing greenfield infrastructure projects worldwide, said the deadline for KKR to announce a firm intention to make an offer was June 3.

KKR did not immediately respond to Reuters' request for a comment.

Shares of John Laing jumped as much as 18.5% to 376.4 pence, their highest level since January 2020, valuing the firm at about 1.86 billion pounds ($2.59 billion).

In March, the company reported a loss before tax of 65 million pounds for the year ending Dec. 31, 2020, compared with a loss of 95 million pounds a year earlier, while net asset value per share slipped to 310 pence from 337 pence.

Last month, John Laing and Macquarie Capital said they would invest 200 million pounds in retirement homes developed by McCarthy Stone to help address the undersupply of elderly accommodation in Britain.

($1 = 0.7195 pounds)

(Reporting by Aby Jose Koilparambil in Bengaluru; Editing by Shinjini Ganguli)