Negative convexity is a concept that plays a significant role in the field of finance and
economics. It refers to the relationship between the price of a
financial instrument and its yield or interest rate. In this context, historical examples and case studies can provide valuable insights into the impact of negative convexity. Several instances throughout history have demonstrated the effects of negative convexity on various financial instruments and markets.
One notable historical example that illustrates the impact of negative convexity is the mortgage-backed securities (MBS) market during the 2008 global
financial crisis. MBS are financial instruments that represent a claim on the cash flows from a pool of mortgages. These securities are subject to negative convexity due to the prepayment option embedded in mortgage contracts. When interest rates decline, homeowners tend to refinance their mortgages to take advantage of lower rates, resulting in higher prepayment rates. This increased prepayment activity reduces the expected cash flows from MBS, leading to a decline in their prices.
During the housing bubble that preceded the financial crisis, interest rates were low, and many homeowners took advantage of easy credit to purchase homes. However, when the housing market collapsed and interest rates rose, many homeowners found themselves unable to refinance their mortgages. This led to a significant increase in mortgage defaults and foreclosures, causing a sharp decline in the value of MBS. The negative convexity of MBS exacerbated the losses experienced by investors, as the decline in prices was more significant than anticipated due to the accelerated prepayment activity.
Another historical case study that highlights the impact of negative convexity is the
bond market turmoil in 1994, often referred to as the "Great Bond Market Massacre." During this period, interest rates rose unexpectedly, causing a sharp decline in bond prices. Bonds with negative convexity, such as callable bonds or mortgage-backed securities, experienced more substantial price declines compared to bonds with positive convexity.
The 1994 bond market turmoil was triggered by the Federal Reserve's decision to raise short-term interest rates in response to concerns about inflation. This unexpected increase in interest rates led to a significant decrease in the value of bonds, particularly those with negative convexity. Callable bonds, for example, allow the issuer to redeem the bonds before maturity, which becomes more likely as interest rates rise. This optionality reduces the value of callable bonds and amplifies their price decline during periods of rising interest rates.
Furthermore, the impact of negative convexity can also be observed in the options market. Options are financial derivatives that provide the right, but not the obligation, to buy or sell an underlying asset at a predetermined price within a specified period. Options exhibit negative convexity due to their non-linear payoff structure. As the underlying asset's price moves further away from the strike price, the change in the option's value becomes less significant.
During periods of high market volatility, options with negative convexity can experience substantial losses. For example, during the
stock market crash of 1987, known as "Black Monday," options traders who held short positions in out-of-the-money put options suffered significant losses due to the negative convexity of these options. As stock prices plummeted, the value of these put options decreased at a slower rate than anticipated, resulting in substantial losses for their holders.
In conclusion, historical examples and case studies provide valuable insights into the impact of negative convexity on various financial instruments and markets. The mortgage-backed securities market during the 2008 financial crisis, the bond market turmoil in 1994, and the options market during the 1987
stock market crash all demonstrate the adverse effects of negative convexity. These instances highlight how changes in interest rates and market conditions can amplify losses and create significant challenges for investors and financial institutions. Understanding and managing negative convexity is crucial for market participants to mitigate risks and make informed investment decisions.