0 Buyer’s Search and Use of Experience-based Information in Extensive Problem Solving Situation Leena Aarikka-Stenroos 1 , Hannu Makkonen 2 1 Researcher, Marketing, Turku School of Economics, leena.aarikka.stenroos@tse.fi 2 Researcher, Marketing, Turku School of Economics, hannu.makkonen@tse.fi Abstract Some buying situations can be considered as extensive problem solving situations, when the newness of the situation and the complexity of the offering challenge the buyer in formulating the problem and finding credible information. In this kind of situation experience-based information provided by a more experienced external source is crucial. This kind of information can be conveyed through reputation, word-of-mouth and references. The paper presents qualitative interview research and contributes by exploring what kind of information buyers seek and what sources and practices they use in order to gain information on previous experiences. The study uses two kinds of contexts as research contexts: knowledge intensive professional services and high-tech innovations. The main findings suggest that the experience-based information provides information on offering, supplier and decision situation itself, and references, word-of-mouth, collegial advice networks and reputation have different kind of roles in focal and continual problem solving situations. Keywords Extensive problem solving, buying, information search, references, reputation, word-of- mouth, knowledge-intensive professional services, innovations