Market research is one of the tools and techniques for the PMI process to plan procurement management. As part of procurement, information about the market will help the team learn what is available for purchase and at what prices. For instance, what materials (resources) or services could help the project. Information from vendors (sellers), conferences, online reviews, and industry analysts may help with the market research.
Market research is described in the PMBOK, 5th edition, section 220.127.116.11.