Abstract: Innovation serves as the strategic support for building a modernized economic system, and optimizing the allocation of innovation resources helps stimulate corporate innovation vitality. Consequently, identifying opportunistic behaviors in corporate R&D activities has become a critical concern for both academia and practitioners. Based on data from A-share listed companies between 2008 and 2022, this paper investigates how corporate managers strategically disclose information in annual reports to conceal R&D manipulation. The findings reveal that companies with higher levels of R&D manipulation tend to produce more complex annual report texts. Mechanism tests show that when firms face greater external scrutiny, attract more investor attention, or have a higher proportion of short-term investors, their managers are more likely to use complex language to obscure R&D manipulation, supporting the management obfuscation hypothesis. Furthermore, such behavior is more pronounced when companies engage in policy rent-seeking, pursue earnings smoothing, or when managers' self-interest is stronger. In addition, the study finds that R&D manipulation undermines the efficiency of resource allocation, thereby negatively affecting companies' innovation performance and competitive position in the product market. This paper not only enriches the literature on R&D activities and annual report textual disclosure but also provides empirical evidence for identifying opportunistic behaviors in innovation activities and optimizing innovation resource allocation.

Key words: R&D manipulation, textual complexity, readability, management obfuscation hypothesis