New York-based investment firm Indigo Capital is considering a bid for troubled office group Regus.
Roberto Woldenberg, managing director of the US hedge fund, said he "could not rule out" substantially increasing his stake in Regus or eventually bidding for the firm.
Indigo has built up its stake in Regus to nearly 12 per cent, understood to be both directly and through a complex dealing arrangement with a money broker.
Mr Woldenberg said Regus had "hidden value" and said Indigo was seeking talks with management about the company.
Shares in Regus, which have slumped amid difficult times in the world economy, jumped seven per cent to 12p in early trading on Friday.
Shares hit a peak in 2001 of nearly 400p but have slid to a low of just 3.25p.
The bid speculation comes weeks after Regus agreed to sell a 58 per cent stake in its UK business to venture capital firm Alchemy in a bid to solve its funding difficulties.
The struggling group, based in Chertsey, Surrey, said at the time there was no alternative to the Alchemy deal apart from placing parts of its business into administration.
Regus, which employs 556 people at 92 centres in the UK, has axed a quarter of its global workforce of 3,500 during the last 18 months.
Latest figures, released in November, showed no end to its troubles as operating losses in the three months to September 30 widened by £2.5 million to £13.1 million.
Shares in Regus accelerated their gains during the session, rising nearly 30 per cent to 14.5p and valuing the company at £84 million.
Regus is however still valued at far below its £2 billion-plus peak.
A spokesman for Regus would not comment on the speculation, while Indigo Capital was not available for comment.
Cantor Fitzgerald, the broker reported to be acting on behalf of Indigo, would not comment on whether it was dealing for the US group.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article