The decrease in pre-tax profit margins due to tax benefits, regarded as evidence of implicit tax realization, can be directly attributed to decreases in sales revenue and/or increases in material costs and labor costs resulting from increased product supply and factor demand driven by greater market competition. However, the magnitude of pre-tax net income also fluctuates due to the effects of selling, general, and administrative expenses, non-operating income and expenses, and extraordinary items, in addition to these influences. Therefore, in situations where changes in sales revenue and pre-tax net income may not be consistent, analysis of decreases in sales revenue and/or increases in material costs and labor costs due to tax benefits will provide new evidence of implicit tax realization. Furthermore, in market structures that are not perfectly competitive, firms may use their market power to shift the burden of implicit taxes onto consumers or factor suppliers. Therefore, research findings on the possibility of implicit tax shifting can provide important implications for understanding the process of implicit tax realization and identifying who ultimately bears the burden. This study seeks to discover new evidence of implicit tax realization through the relationships between sales revenue and tax benefits, and between prime costs (material costs and labor costs) and tax benefits, and to investigate the possibility of implicit tax shifting due to imperfectly competitive market structures. To this end, regression models were employed with the net sales-to-equity ratio (NSOE), direct materials-to-equity ratio (DMOE), and direct labor-to-equity ratio (DLOE) as dependent variables, adding market concentration ratio (CR4) and market share (MS)—used as market structure characteristic variables in Challihan and White (1999)—as independent variables to the Wilkie (1992) model. The results showed that net sales had a significant negative relationship with the tax benefit measure and a significant positive relationship with market structure characteristic variables. This implies that greater tax benefits lead to decreased sales, meaning that firms bear implicit taxes in the form of reduced sales due to increased market competition. The positive relationship between sales and market structure characteristic variables suggests the potential for implicit tax shifting onto consumers through market power, but no direct evidence of implicit tax shifting was found. Analysis of prime costs (material costs and labor costs) found no evidence of implicit tax realization through cost increases, but did discover the possibility that firms exercise market power to reduce labor costs, thereby shifting implicit taxes onto workers.