The research aim is to discover the cause which led to the sharp decrease in revenue of Fuso truck in late 2021 period. In order to fulfill the research objectives, the research has been using both primary and secondary data, which is collected from the company data, press release, journals, books, interviews…etc. Eventually, it is discovered that, due to the uncompleted process of market research procedure, Fuso has lost its competitive advantages among the other direct competitors on the market, which led to the sharp decrease in revenue by late 2021. During the interview with key PIC, they all agree that the personnel rotation between departments definitely has an impact on the market research activity, but in overall, it is not likely to be the main point, but unstandardized market research process should be accounted as a cause for the problem. Over years, the market research process has been established in THACO but not in a completed process, which is mainly dependent on the experiences of employees. That’s when issues happen, since the market and development team has received some new members who are not skillful in this area. As a result, some steps are missed and the research method applied is not fit with the targeted customers, which led to the poor quality of market research during that time. Based on the discovered issues, the research also done some solution proposal for the problem owners and outsourcing market research activities is considered as the best move to turn back the market share as well as the chance for company to learn and build the standardized process for long-term strategy.