By Aakash B and Yadarisa Shabong
(Reuters) - Canadian security firm GardaWorld on Wednesday went hostile with its bid to buy G4S (CSE:G4S) Plc with a cash offer valuing its larger rival at 2.97 billion pounds ($3.81 billion), weeks after the British company rejected an earlier proposal.
G4S had rejected GardaWorld's sweetened 190 pence per share offer earlier in September, calling it "highly opportunistic." It also rejected two prior proposals in June for 145 pence per share and 153 pence per share each.
Shares in London-listed G4S were up 4.2% at 197.1 pence by 1125 GMT, above the 190 pence offer made by GardaWorld's subsidiary Fleming Capital Securities.
Since GardaWorld made its offer for G4S public on Sept. 14, G4S shares are up 30%.
"The G4S Board has behaved in a cavalier way by rejecting our potential offer out of hand," GardaWorld's Chief Executive Stephan Cretier said.
"We look forward to meeting with investors to explain the challenges ahead and why this is a full and fair price," Cretier added.
G4S, one of the world's largest private security companies, was not immediately available for comment.
The latest offer, which is for the same amount as the one made a few weeks ago, represents a premium of 0.5% to G4S' Tuesday's closing stock price. Analysts had likened the takeover approach as "the tiddler swallowing the whale".
GardaWorld's interest in G4S was made known last year, when it considered a cash offer for some or all of G4S, but by May had opted not pursue a deal.
Over the past year G4S has had to overcome a series of setbacks, including the loss of a contract to run a Birmingham prison, and a decision by Norway's wealth fund not to invest in the company.
It sold off most of its cash-handling business in February to U.S. peer Brinks Co.
($1 = 0.7790 pounds)