The takeover battle for Alamito Co. intensified.

A four-way takeover battle for the Arizona-based electricity wholesaler rapidly escalated as three of the suitors leapfrogged each other’s bids. The day began with Ventana Electric, a company formed by Alamito management, raising its offer for the company to $140 a share from $128 a share. Within hours another suitor, an investor group called Megawatt Corp., lifted its offer to $142 from $128 for each of Alamito’s 2.3 million common shares outstanding. Then, after the NYSE had closed, a third investor group, called Osceola Energy, sweetened its earlier offer to $155 a share, or $356.5 million, from $140.