(Bloomberg) -- GardaWorld is planning to increase its hostile offer for G4S Plc before a looming deadline, according to people familiar with the matter, the latest twist in the hotly contested pursuit of the British security provider.The Canadian security firm is likely to announce an increase before a Wednesday deadline, said the people, who asked not to be identified because discussions are private. The Montreal-based company hasn’t made a final decision and a price couldn’t be immediately learned.Some top G4S shareholders have been pushing for suitors to raise their bids to at least 220 pence per share as a starting point for more serious negotiations, the people said. Shares of G4S rose as much as 9.9% in London Tuesday and closed at 229 pence, giving the company a market value of about 3.6 billion pounds ($4.8 billion).Garda, with the backing of main shareholder BC Partners, announced an all-cash offer of 190 pence a share, or 2.9 billion pounds, in September. G4S and some key shareholders rejected it as too low. As of Nov. 30, barely anyone had accepted the bid, increasing the pressure on the Canadian suitor to improve its offer or move on.U.S. competitor Allied Universal Security Services LLC is also preparing a fresh offer for G4S after the target rejected a proposal of at least 210 pence per share, according to people familiar with the deliberations. The American company, which is backed by Canadian pension fund Caisse de Depot et Placement du Quebec and buyout firm Warburg Pincus, has been waiting to see if Garda bumps before making a final decision on a new bid, they said.Allied Universal is lining up financing after holding behind-the-scenes talks and getting access to G4S’s books, helping it calculate a higher offer based on potential synergies and the business outlook, the people said. They have a week after the Dec. 2 deadline to make a counteroffer.Representatives for Allied, Garda and G4S declined to comment.G4S Chief Executive Officer Ashley Almanza said in an interview in October that the company hasn’t seen any mergers that make sense and will push ahead with a turnaround plan.Garda CEO Stephan Cretier has publicly accused G4S management of losing “track of reality.” He has also taken aim at Allied Universal’s bid, saying it would get blocked by U.S. antitrust authorities. But Allied Universal secured that approval last month, undermining the argument.Garda, for its part, has received European approval.(Updates with G4S closing price in third paragraph)For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.