"Rival companies" refers to businesses that compete against each other in the same industry or market. They are competing for customers, sales, and market share by offering similar products or services. Full definition
Be sure to have offers from rival companies on hand and ready to quote. (bgr.com)
Some of them I think may work for rival companies and pose as customers trying to be helpful. (dogfoodinsider.com)
When they realize they've been hired at rival companies, however, they need to keep their romantic relationship a secret or risk losing everything they have. (kuriousity.ca)