Negative
convexity can have significant implications for investors in terms of potential returns. Convexity refers to the curvature of the price-yield relationship of a
fixed-income security, such as bonds or mortgage-backed securities (MBS). When a security exhibits negative convexity, it means that its price-yield relationship is non-linear and asymmetric. In other words, the price of the security does not change in a proportional manner to changes in its
yield.
One of the key impacts of negative convexity on potential returns for investors is the phenomenon known as "price
risk." Price risk arises from the fact that when
interest rates decline, the price of a fixed-income security with negative convexity may not rise as much as expected. Conversely, when interest rates rise, the price of such a security may fall more than anticipated. This asymmetry in price movements can lead to unexpected losses for investors.
To understand this impact, let's consider an example. Suppose an
investor holds a mortgage-backed security with negative convexity. If interest rates decline, homeowners are more likely to
refinance their mortgages, resulting in prepayments of
principal. As a result, the investor receives the principal earlier than expected. However, since the investor paid a premium for the security, they may not be able to reinvest the prepaid principal at the same yield as before. This reinvestment risk can lead to lower overall returns.
Conversely, when interest rates rise, homeowners are less likely to refinance their mortgages due to higher borrowing costs. This means that the investor's principal is repaid more slowly than anticipated. As a result, the investor is exposed to a longer duration and is locked into a lower yield for a longer period. This extension risk can also result in lower returns.
Another impact of negative convexity is the potential for increased
volatility in the price of a security. As interest rates change, the price of a security with negative convexity can experience larger and more abrupt price swings compared to a security with positive convexity. This increased volatility can make it challenging for investors to accurately predict and manage their investment risks.
Furthermore, negative convexity can affect the performance of hedging strategies. For example, investors may use
interest rate derivatives, such as options or
futures, to hedge against interest rate risk. However, the presence of negative convexity in the underlying securities can make it difficult to construct an effective hedge. This is because the non-linear price-yield relationship of the security may not align with the linear price-yield relationship of the
derivative instrument, leading to imperfect hedging and potential losses.
In summary, negative convexity can have significant implications for investors' potential returns. It introduces price risk, reinvestment risk, extension risk, increased price volatility, and challenges in constructing effective hedging strategies. Therefore, investors need to carefully consider the presence of negative convexity when evaluating fixed-income securities and managing their investment portfolios.