Buyers and suppliers in all market transactions form various types of buyer-supplier relationships. Buyer-supplier relationships are affected by many different factors, including nationality, culture, buyer and supplier reputations, transaction satisfaction, trust, and so on. Partner stances, which involve trust, fear, and greed, open up the possibility for “opportunism” in buyer-supplier relationships, which may worsen or even dissolve partnerships in the process. Based on the case of Taiwan bicycle trader A company, this study explores examining the formation and transformation in buyer-supplier relationships during the more than 20 years of transactions between Company A and German bicycle manufacturer Company M, pairing this with analysis conducted using academic frameworks on buyer-supplier relationships and partnerships, to serve as a reference for the industry.