大法官解釋對金融業股價及成交量之影響－－以釋字 693號為例

Impact of Constitutional Interpretation No. 693 on Stock Price and Trading Volume of Financial Institutions

金融機構之證券交易課稅爭議，往往涉訟金額大，其勝敗對營運活動及財報數字皆產生重大影響，有時還須訴諸司法院大法官會議作成釋憲解釋。一旦釋憲解釋公布，纏訟多年的所有稅務爭議，乃至應付稅款所需的現金流量等同塵埃落定，影響應可觀。根據現金流量假說，當公司未來現金流量改變時，其市值亦會受到影響。本文透過現金流量假說，利用事件研究法探討2011年底司法院公布大法官釋字693號權證課稅解釋時，相關金融機構之股價及成交量是否產生異常波動。本研究之實證結果發現，釋字693號公布時，因發行權證而未預期現金流出的應補繳稅額愈高者，事件期間之累積異常報酬率下跌愈多，顯示股市投資人對於大法官解釋之反應，符合現金流量假說之預期，至於成交量則未有影響。 The outcomes of tax litigation, especially in cases involving controversies over securities trading among financial institutions, usually have a critical impact on the operational activities and financial performance of litigants. The Constitutional Interpretation is the final resort for judicial controversies that might have lasted for years and thus plays a decisive role in the litigation process. From the perspective of cash flow hypothesis, a company's market value is affected by changes in future cash flows. The empirical results of this study reveal that during the event period when Constitutional Interpretation No. 693 was declared, a considerable decline of cumulative abnormal returns was observed along with high unexpected cash outflows on tax due, this is consistent with the cash flow hypothesis; however, no abnormal trading volume was observed.