Abstract:
In many industries, complexity and uncertainty have increased to the point that competing
autonomously is no longer an option. The characteristics of products produced and processes involved in
manufacturing contribute to the complexity of the relationship. Speed, quality, and flexibility are being
emphasized as means of responding to the unique needs of customers and markets. Implementation of supply
chain integral relationships has been advocated as the means of increasing competitiveness of firms. The study
specifically addressed the effect of Idiosyncratic Partner Investment on the Performance of cosmetics
manufacturing firms in Nairobi County, Kenya. Relational View theory was adopted in the study. The study
adopted Positivism Research Philosophy. Cross-sectional survey research design was used in the study. The
unit of analysis was 714 employees working in the procurement departments in cosmetics manufacturing firms
in Nairobi County, Kenya. A sample of 256 was selected from the target population using a Multi Stage
Sampling Technique. Primary data was collected using self-administered semi-structured questionnaires which
were dropped and picked later. Both descriptive and inferential statistics were used to analyse the collected
data. Moderated Multiple Regression (MMR) was used to analyse the relationship between the predictor
variables and performance. Pilot study reliability results showed that all our Cronbach’s alpha coefficients
were above 0.7, implying that the research instruments were reliable. The findings of the study showed that
there was a positive and statistically significant correlation between idiosyncratic partner investment and
performance (r=.529, p<0.01). The study concludes that idiosyncratic partner investments positively affect the
performance of cosmetics firms. The study recommends that cosmetics firms should engage idiosyncratic
partner investments, and make major investments, in time and effort to learn about the business practices of
their suppliers, specifically for relational exchange. The results of the study will contribute to greater
understanding of the supply chain integral factors that leads to outstanding performance of firms.