現行租賃會計準則以特定條件區分租賃會計處理為融資租賃與營業租賃，營業租賃交易排除於資產負債表外，使企業進行資產負債表外融資之機會增加，一直備受實務界與學術界批評。IAS 17之修正草案（ED Lease）擬將租賃合約全面資本化之會計處理（即營業租賃亦須在租賃期間開始日於資產負債表中認列租賃交易相關之資產及負債），有助於允當表達租賃合約之經濟實質。本文以臺灣上市公司為研究對象，探討營業租賃資本化負債之市場評價以及營業租賃資本化與公司系統風險之關聯。實證結果包含：（1）投資人評價營業租賃合約負債為顯著負值，顯示投資人認為營業租賃合約之承租人對租賃支付義務（營業租賃合約負債）合乎負債的定義；另外，投資人對於營業租賃合約負債與認列於資產負債表中之付息負債之評價並無顯著差異。（2）未調整營業租賃資本化之負債權益比及調整營業租賃資本化之負債權益比，均與公司系統風險呈現顯著正相關，但調整營業租賃資本化負債後之負債權益比，並未能顯著增加對公司系統風險之解釋力。本文實證結果支持IAS 17修正草案（ED Lease）之修訂方向，即營業租賃之應付租賃款合乎負債之定義，因此營業租賃亦應資本化。

Current accounting standards for leases distinguish between capital lease and operating lease (i.e. leases are kept on- or off-balance sheet). In fact, critics by practices and academic argue that the chance of off-balance sheet financing due to leases accounting standards is increasing. In an effort to more faithfully present lease contracts in financial statements, International Accounting Standards Board (IASB) propose to have all lease contracts capitalized and thereby to reduce off-balance sheet activities. Based on the data from Taiwan listed firms, this paper examines whether market's valuation of lease liability under operating leases is the same as firms' other liabilities. In addition, I examine whether the debt to equity ratio adjusted for capitalization of operating leases is related to the measurement of firms' systematic risks. The empirical results show:(1) the valuation coefficient of lease liability of operating lease is significant negative despite operating leases are not formally capitalized on the book, and the valuation coefficient of lease liability of operating lease is not significantly different from the coefficient of other liabilities; (2) both the debt to equity ratio adjusted for capitalization of operating leases and the debt to equity ratio unadjusted for capitalization of operating leases are significantly positive associated with the firms' systematic risks. Yet, the adjusted ratio yields no incremental explanatory power over the unadjusted ratio. The findings support the requirement by IASB ED Leases to eliminate the classification of leases as either capital or operating, and instead to require all leases be capitalized.