This study aims to examine, on theoretical grounds, the sensitivity of corporate investment to internally generated cash flow in light of two central explanatory frames: financing constraints and the quality of financial disclosure. First, the study explores the emergence of investment–cash flow sensitivity as a research construct. In this part, we introduce the concept of cash flow sensitivity, then highlight the principal motives behind its emergence, its importance, and its objectives. Second, the study focuses on the role of financing constraints in shaping cash flow sensitivity. In this part, we examine the principles of the financing constraints theory, its implementation through standard empirical proxies, and its main determinants. Third, the paper examines the relationship between financial disclosure quality and investment–cash flow sensitivity. In this part, based on existing research, we clarify the role of high-quality disclosure in mitigating information frictions and reducing the dependence of investment on internal cash flow. Finally, we summarize how financing frictions and disclosure quality jointly shape the conversion of cash flow into productive investment, with consequences for capital allocation and the broader economy.