Bond Fundamentals and Pricing › Limitations and Practical Considerations

Bond pricing in practice involves complexities beyond this simplified framework. Understanding these limitations helps practitioners apply theoretical models appropriately.

The assumption of a single discount rate (the YTM) for all cash flows is a significant simplification. In reality, interest rates vary by maturity, forming a yield curve. Short-term rates may differ substantially from long-term rates, and using a single rate ignores this term structure. More sophisticated approaches discount each cash flow at its own appropriate rate, a topic we'll address when discussing yield curve construction.

Credit risk affects corporate debt and can affect sovereign debt as well. Default probabilities and recovery expectations can change with issuer finances and economic conditions. A constant-spread model does not represent those changing exposures. Embedded options, such as an issuer call or holder put, can change payment timing and require valuation consistent with the contractual exercise rights.

Liquidity also influences prices. A bond that trades infrequently may have a wider bid-ask spread and a price that doesn't fully reflect current market conditions. Two bonds with identical cash flows may trade at different prices simply because one is more liquid than the other.

Despite these limitations, the discounted cash flow framework remains the foundation of bond analysis. Understanding this framework is essential before tackling more advanced topics like duration, convexity, and term structure models.