The world's largest security services firm G4S has rejected a 1.55 billion pound ($2.5 billion) offer for its cash solutions business from British private equity group Charterhouse Capital Partners .
G4S, which is trying to recover from a series of damaging incidents with the British government, on Monday said the bid was "highly opportunistic" and undervalued the business.
The cash solutions unit, whose services includes transporting cash using high-security vans, accounted for about 18 percent of G4S's 7.3 billion pound group turnover last year.
"G4S is committed to invest in its core businesses, including cash solutions, which have strong opportunities for sustainable profitable growth," the company said.
Shares in G4S opened 2 percent higher and at 0830 GMT were trading up at 1.1 percent at 261.3 pence.
"It does feel like the offer from Charterhouse has been a little bit opportunistic, these are businesses that private equity loves - decent cash generation, higher returns," said Panmure Gordon analyst Mike Allen.
"It's quite a stable business really, it's not produced to its full potential in recent years because of interest rates being so low... At the moment G4S need a business like that while they're trying to find their feet when there's so much uncertainty with the UK government," he said.
The government, one of the company's largest clients, has put all its contracts under review after a series of blunders, the latest being the discovery that it and rival Serco had charged for tagging criminals that were either dead or in prison.