會計穩健性與投資之分離均衡、有扭曲的分離均衡及混同均衡

Accounting Conservatism and Investment: Separating Equilibrium, Separating Equilibrium with Distortion, and Pooling Equilibrium

本研究旨在探討公司治理與股東的投資關係，本研究將會計穩健性的偏好的企業分為兩類，分為消極公司治理的企業與積極公司治理的企業。會計穩健水準常會影響股東的投資金額，探討兩種企業型態的分離均衡、有扭曲的分離均衡與混同均衡之存在條件。本研究發現第一，當消極公司治理的企業相對於積極公司治理的企業的原始最適穩健決策為大時，則滿足分離均衡的要件。第二，只要當消極公司治理的企業或積極公司治理的企業的任何一方，其所為股東所創造的固定利益與穩健水準所產生的單位利益二者，皆較另一類型公司為大時，則有扭曲的分離均衡不存在，僅會發生分離均衡。第三，若消極公司治理的企業為股東所創造的固定利益高（低）於積極公司治理的企業之門檻值，則消極公司治理的企業（積極公司治理的企業）將採取有扭曲的分離均衡。第四，當一方企業模仿另一方企業時，可能產生混同均衡，使雙方選擇相同的會計穩健水準，此時會計選擇不再揭露公司型態，投資人遂依據觀察會計穩健水準所形成的後驗信念決定投資水準。

This study analyzes how corporate governance shapes shareholders’investment decisions through firms’choices of accounting conservatism. Firms are classified into two types according to their tolerance for conservatism: those with passive corporate governance and those with active corporate governance. Within a signaling framework, accounting conservatism affects investors’beliefs and, in turn, their investment levels. The model characterizes the conditions under which separating equilibrium, separating equilibrium with distortion, and pooling equilibrium emerge. The analysis yields four main results. First, a separating equilibrium arises when the intrinsically optimal level of accounting conservatism chosen by firms with passive corporate governance exceeds that of firms with active corporate governance. Second, when one type of firm generates both higher fixed and marginal benefits of accounting conservatism for shareholders than the other, a distorted separating equilibrium does not arise, and only a separating equilibrium is sustained. Third, a separating equilibrium with distortion emerges when the fixed benefit generated by one type exceeds a threshold relative to the other. Finally, when one type optimally mimics the other, a pooling equilibrium arises in which accounting choices no longer reveal firm types, and investors base their investment decisions on posterior beliefs inferred from observed accounting conservatism.