After the financial crisis, it has been widely recognized that counterparty default risks have serious consequences and that there are remarkably large differences in various interest rates. As a result, the methodology for pricing derivative securities has been modified: Currently, the price of a derivative security is expressed as the so-called XVA, which is the risk-neutral price plus total valuation adjustment. In this paper, we aim to provide a theoretical interpretation of XVA: Some valuation adjustments are interpreted as the ``$0$th-order'' approximation of XVA. Further, we describe a sufficient condition to ensure the arbitrage-free property of the $0$th-order price approximation.