Before revision:  We will see later that absence of market frictions is an inherent assumption for the margin requirement in Basel III. In addition, as we consider entity-specific information in bilateral pricing , law of one price does not hold. Moreover, inclusion of funding spreads causes asymmetry in individual pricing.
After revision:  We will see later that absence of market frictions is an inherent assumption for the two parties deduce different fair prices for derivative contracts even under the same pricing methodology and parameters.