What is the ruling on my private company supplying the company I work for, given that the purchase process will not be through me, and am I obligated to inform the purchasing officer that I am a partner in the supplying company?

It is cautioned that the questioner might be an agent for his company in purchasing, while his own private company is the seller. In this case, he must obtain permission from the company he works for, because an agent for purchasing cannot buy from himself unless he has the permission of his principal. However, if he is not an agent for the company, then there is no harm in his private company selling to it, or contracting with it to supply what it needs.