Question: Why treasury yields are important for bond holders?
Answer: All the returns in the bond market are compared with the treasury yields. Because treasury the safest debt instruments, everybody is looking for the more return then treasury, if invested in any other bond. Because they are riskier than treasury. Most other bonds yields are compared to the Treasury levels and are quoted as spreads off appropriate Treasury yields. To the extent that the yields of all fixed income securities are interrelated, their prices respond to changes in Treasury rates.
Question: How do you quantify the interest rate risk?
Answer: Interest rate risks are quantified using the Duration and this is one of the most common way. Duration is the approximate percentage change in the price of a bond or bond portfolio due to a 100 basis point change in yields.
Question: What does a yield-curve represent?
Answer: The yield-curve shows the relationship between the yield on bonds of the same credit quality with different maturities.
Question: Can you use Yield Curve Risk with MBS (Mortgage Backed Security)
Answer: No, Yield-curve risk is the exposure of a portfolio. Yield-curve risk is mainly used for portfolio management, but not with mortgage-backed securities, it is primarily a risk that must be dealt with at the portfolio level.