| Abstract: | 文獻上已有產品市場競爭 (PMC) 對公司資訊揭露水準影響的研究，但結論分歧，本研究認為PMC之內生性問題可能是重要原因。此處內生性是指資訊揭露水準也影響PMC (即兩者互為因果的關係)，及 (或) 遺漏會影響資訊揭露水準的重要因素。過去文獻有類似發現，公司的資訊揭露可能影響PMC；本研究目的即在檢視PMC的內生性是否導致PMC對公司資訊揭露水準有所影響的結論錯誤或不完整，以及PMC如何影響 (若有) 資訊揭露水準。本研究之樣本是台灣上市、上櫃公司 (排除金融、保險業)，使用證基會的資訊揭露評鑑結果衡量資訊揭露水準，資料期間為2005至2014年，利用工具變數法解決PMC內生性問題，同時考慮是否忽略文獻所提及影響資訊揭露的重要變數，並以多個指標衡量PMC以降低衡量誤差。結果發現：未考慮市場競爭之內生性時，發現產品市場競爭 (集中度低) 對次年的資訊揭露有負向影響，且市場競爭的不同指標皆如此。考慮市場競爭的內生性後，基本上仍發現市場愈競爭則公司資訊揭露程度愈低。表示競爭者進入的威脅對既有廠商的影響頗大，即資訊揭露的成本大於效益，使得公司減少額外資訊的揭露。至於資訊揭露是否也影響市場競爭，結果也是負向影響，亦即資訊揭露水準高者，潛在競爭者卻步，導致市場不競爭。
過去文獻所提及同時影響市場競爭與資訊揭露的重要變數有三個：進入成本、產業規模和產品替代性，實證結果發現：前兩者高度相關；進入成本愈低，次年產品市場愈不競爭，概隱喻公司資訊揭露程度高可以阻卻新廠商進入所致，與過去文獻之主張相同。產品越可替代時，公司較不願揭露資訊，以免競爭者知悉而導致競爭加劇；越不具替代性，公司較願揭露資訊，因為即使競爭者蒐集到資訊也難以生產該產品。
There is already research on product market competition (PMC) in the literature, but the conclusions are different. This study suggests that the endogeneity problem of PMC may be an important reason. Endogeneity means that the information disclosure level also affects the PMC (that is, they have a causality), and/or omits the important factors that affect information disclosure. Similar findings have been made in the past literature that company's information disclosure may affect PMC. The purpose of this study is to examine whether PMC endogeneity causes the conclusion that PMC has an impact on the company's information disclosure level is wrong or incomplete, and how PMC affects (if any) information disclosure. The sample of this study is both the listed and OTC firms in Taiwan (excluding the finance and insurance firms), using the evaluation ranks of the Securities and Futures Commission to measure the information disclosure level. The data period is from 2005 to 2014, using the instrument variable method to solve the PMC endogeneity. Moreover, the study considers whether the important variables affecting information disclosure mentioned in the literature are ignored, and measures the PMC by various indicators to reduce the measurement error. This study finds that when the endogeneity of market competition is not considered, product market competition (i.e., low concentration) has a negative impact on the information disclosure for the following year, and the results are the same for different indicators of market competition. After considering the market competition endogeneity, it is still basically found that the more competitive the market, the lower the company's information disclosure. That is, the threat of competitors' entry has a great impact on the existing firms, and the cost of information disclosure is greater than the benefit, which induces the company to reduce the disclosure of additional information. As to whether the information disclosure also affects market competition, the result is also negative impact, namely, when the information disclosure is high, and the potential competitors are afraid to enter, resulting in the market does not compete.
There are three important variables mentioned in the past literature that affect market competition and information disclosure: entry cost, industry size, and product substitution. The empirical results show that the first two are highly correlated; the lower the entry cost, the less competitive the product market is in the next year. This result likely indicates that the company's information disclosure is high to prevent the entry of potential firms, the same as the previous literature. The more substitutable a product is, the less willing the firm has to disclose information so that competitors are not aware of information and do not enter to compete intensely. The less substitutable makes the company more willing to disclose information because even if competitors collect information, they difficultly produce the products. |
