The article introduces a new risk measure called mark to market value at risk (MMVaR) to better assess market risk in financial institutions with daily settlements. MMVaR is an improved version of the commonly used value at risk (VaR) measure, providing more accurate risk calculations. Real data analysis shows that risks calculated using MMVaR are about 20% higher than those using VaR, aligning with Basel III's capital adequacy ratio requirement. This new measure can help financial institutions better manage their daily risks.