Bonds are simple to buy and subtle to understand
A bond's pitch is straightforward: lend money, collect interest, get your principal back. But how a bond — and a portfolio of them — actually behaves when interest rates, credit conditions, and the yield curve move is anything but simple. Fixed-income analytics is the toolkit for understanding that behavior across yield, duration, convexity, spread, credit, maturity, cash flow, and curve scenarios. Skip it and you are holding instruments whose risk you cannot describe.
Yield is a starting point, not the answer
Yield tells you the return a bond offers at a given price, but several yield measures exist — current yield, yield to maturity, yield to worst — and they answer different questions. Yield to worst, for instance, assumes the least favorable call scenario, which matters for callable bonds. Quoting "the yield" without specifying which one is how investors misjudge what they actually own.
Duration: the first-order rate risk
Duration is the single most important fixed-income concept. It measures how much a bond's price moves for a given change in interest rates — a duration of 7 means roughly a 7% price drop if rates rise one percentage point. It is the primary gauge of interest-rate risk, and at the portfolio level it tells you how exposed the whole book is to rate moves. Two portfolios with the same yield can have very different durations, and therefore very different risk, which is why duration — not yield — is the right first question about a bond portfolio.
Convexity: the correction duration misses
Duration assumes price moves in a straight line with rates, but the real relationship is curved. Convexity measures that curvature, and it matters most when rate moves are large. Positive convexity is friendly — prices fall less than duration predicts when rates rise and gain more when rates fall. Ignoring convexity means underestimating how a portfolio behaves in exactly the volatile conditions where accuracy matters most.
Spread and credit: getting paid for risk
Government bonds carry rate risk; corporate and other bonds add credit risk, and spread is the extra yield that compensates for it. Option-adjusted spread (OAS) refines this by accounting for embedded options like calls. Monitoring spread, spread duration (sensitivity to spread changes), credit distribution across the portfolio, and default-probability inputs is how you judge whether you are being adequately paid for the credit risk you hold — and whether a credit is quietly deteriorating before it shows up in the price.
Key-rate exposure and the curve: not all rate moves are parallel
A subtle but crucial point: the yield curve rarely shifts uniformly. Short rates can rise while long rates fall, or the curve can steepen or flatten. A single portfolio-duration number assumes parallel shifts and hides this. Key-rate duration breaks exposure down by maturity point, revealing where on the curve the portfolio is actually sensitive. Curve-shift and horizon-return analysis then test how the portfolio performs under specific curve scenarios — the realistic ones, not just a uniform move.