The bidding for Alamito Co. continued to escalate.

A management group that organized a company called Ventana Electric sweetened its bid to $147 a share, or $338 million, from $140. Alamito, a Tucson-based wholesaler of electric power, also is the target of three other offers. An investor group called Megawatt raised its offer to $142 from $128 for each of Alamito’s 2.3 million common shares outstanding. Another investor group, Osceola Energy, responded by lifting its bid to $155 from $140 in cash and preferred stock for each Alamito share.