摘要
在傳統的成本習性模型中，將成本區分為固定成本及變動成本兩類，並認為變動成本會隨著成本動因數量呈等比例變化。然而，近來國內外實證研究發現當成本動因數量增加時所造成成本增加之程度會大於當成本動因數量減少時其成本之減少，此現象稱為「成本僵固性」。本研究旨在延伸國內外對於成本僵固性之成本習性特殊情況之研究，探討經理人之樂觀程度與成本僵固性之關聯性，認為若經理人對公司未來狀況樂觀，其會認為銷貨減少是短暫的現象或往後銷貨復甦較繼續減少的機率大而較不願意裁減資源，以避免因為裁撤資源而需付出的資源調整成本及未來需重新取得資源的成本。參考Banker et al. (2014)之研究建立分析模型，本研究並根據行為財務學文獻設計以持股數及資本支出為基礎之方法衡量經理人之樂觀程度，檢驗在銷管費用及其他成本項目中，經理人之樂觀程度是否使成本僵固性現象更加嚴重。 本研究使用國內上市櫃公司1991年至2013年之樣本，實證結果顯示在銷管費用、銷貨成本、銷售費用及管理費用中皆有成本僵固性之存在，然而研發費用卻無發現此種現象。而不論以持股數為基礎或資本支出為基礎，本研究發現當經理人的態度為樂觀時其成本僵固性會更加嚴重，驗證經理人對於未來的態度亦會影響企業之成本習性結構。本研究另以前期持股數和前期資本支出變動、不同之經理人任期的選取樣本方式及連續變數取代虛擬變數等不同衡量方法，亦都證實經理人之樂觀程度會與成本僵固性呈現正向關係。此外，本研究結果顯示當公司獨立董事的比例愈大時，樂觀程度即不會顯著的影響成本僵固性，顯示獨立董事可能抑制經理人的樂觀行為。
並列摘要
Recent research on cost behavior has revealed that costs do not change proportionately with changes in sales, showing that costs increase in response to the increase in sales, but do not decline proportionately with the reduction in sales. This asymmetric cost behavior is termed as “sticky costs”.This study extends prior researchby examining the relationship between the executive optimism and the stickiness of costs based on the hypothesis: when managers are faced with a decline in sales, there are some who consider the decline to be temporary, and expect sales to rebound in the near future; thus, they would keep the resources to prevent the costs of adjustment and reacquiring resources. Following the prior research of behavior finance, this study measuresexecutive optimism by using share-based method and capital expenditure-based methodto investigate if the executive optimism results in greater cost stickiness in SG&A and other costs. Using a sample of listed companies of Taiwan from 1991 to 2013, I found that the stickiness cost phenomenon truly exists in Taiwan and my results provide strong evidence that the executive optimism causes the costs stickier no matter applying either method of optimism measurement. In addition, I also found similar results as the main tests when using some different ways to measure optimism such as the change of shareholdings and capital expenditure in prior year.This study further investigates the impact of independent directors on executive optimism, the result is expected and found that independent directorsmitigate the positive effects of executive optimism on the stickiness of costs.