A "competing bidder" refers to someone who is participating in an auction or bidding process to acquire something, such as an item or property, and is competing against others who also want to acquire it. Full definition
Plenty of competing bidders and sideline observers thought, well, that's an optimistic amount of money to spend on a story of crushing... (chicagotribune.com)
The probers believe he may have secured a copy of the document — detailing proposals by competing bidders — before his client made key improvements to its winning bid to run the video lottery parlor, sources said. (nypost.com)
RFPs basically lay out all the specific project needs and questions the customer has, in one document, which is sent to numerous competing bidders. (entrepreneur.com)