Helical's shares rose 5% to 372.5 pence after the news, giving the company a market valuation of 446 million pounds. The Sunday Times had reported that Helical received a bid of around 500 million pounds from an unnamed U.S. private equity group.

Helical said the unsolicited offers were at a significant discount to its EPRA net asset value (NAV) and therefore did not reflect the fair value of the company.

EPRA NAV is a key industry metric that reflects the value of a firm's buildings.

The Sunday Times said the bid valued Helical at a significant premium to the stock's Friday closing of 355 pence and market capitalization of 425 million pounds, but at less than its net asset value of 567 million pounds.

Helical, which operates primarily in London and Manchester, had an NAV of 482 pence per share at the end of March, while the 500 million pound offer would represent about 413 pence per share, Peel Hunt analysts said.

"In our view the market has been undervaluing Helical for some time now and this third party interest – while perhaps not at an acceptable level – reflects this," the analysts said.

(Reporting by Samantha Machado in Bengaluru; Editing by Saumyadeb Chakrabarty)