The battle over UK-based G4S took an interesting turn this morning as Canadian-based security and guarding firm GardaWorld declined to raise its bid. This places U.S.-based Allied Universal in a winning position. A deal for Allied Universal would launch the company into a security firm with a global reach.

Allied is backed by private-equity firm Warburg Pincus LLC and Canadian pension fund Caisse de Depot et Placement du Quebec. The company's current bid is $5.3 billion to acquire G4S.

GardaWorld and Allied had been scheduled to go into a rare bidding auction held by U.K. regulators this week, but a decline of GardaWorld to raise its current bid of approximately $3.30 per share leaves Allied with the highest offer. 

G4S has roughly 500,000 employees worldwide.