In a surprise move, France’s third cellco, Bouygues, has raised its offer for its larger rival, SFR, trying to fight off lead bidder Altice. The two firms had both made offers for SFR, the mobile operator arm of media giant Vivendi, but Vivendi had chosen to enter exclusive negotiations with Altice, which wants to merge the cellco with its cable company, Numericable. Many analysts had expected Bouygues to accept defeat and, instead, pursue a merger with Iliad, which owns France’s fourth mobile operator, Free Mobile. However, it has come back with an improved bid of €13.5bn ($18.1bn) in cash and a 21.5% stake for Vivendi in the combined entity, an increase of €1.85bn in cash and valuing SFR at €17.4bn…