Speaking of which, there are plenty examples of bidders for certain jobs. Tax farmers in Asia Minor after Pompey's annexation are an example of this as are companies owning boats to transport equipment (either 2nd Punic war or afterwards with regards to shipping supplies to Iberia).

One of the best examples of this contracting is just outside the Porta Maggiore. It is the Tomb of Eurysaces. He was a freedman and baker during the reign of Augustus who built his fortune when he was contracted to supply bread to the Roman army. Talk about a lucrative deal.