CFA Level I: Yield Curve Strategies

Yield curve strategies are the cornerstone of active fixed income portfolio management. Understanding how to position a portfolio in anticipation of changes in the shape and level of interest rates separates passive investors from skilled managers who seek to add alpha. Core frameworks and tactical trades are used to exploit expected movements in the yield curve, which is the graphical representation of interest rates across different maturities.

The Foundation: Yield Curve Shapes and Economic Expectations

The shape of the yield curve is not random; it embodies the market's collective expectations for future economic growth, inflation, and monetary policy. A normal, upward-sloping curve suggests expectations of future economic expansion and potentially higher rates. A flat curve indicates uncertainty or expectations that central bank policy will tighten. An inverted, downward-sloping curve is a powerful signal of anticipated economic contraction, as investors expect future short-term rates to fall.

Your strategy begins by formulating a view on how these expectations might change. Will the entire curve shift up or down in a parallel shift? Will short-term rates move more than long-term rates, causing a non-parallel shift such as a steepening or flattening? Your portfolio's structure must be deliberately chosen to capitalize on your forecast while managing risk.

Passive Portfolio Structures: Bullet, Barbell, and Ladder

Before engaging in active trades, you must understand the three fundamental passive portfolio structures. Each has distinct exposure to yield curve movements.

A bullet portfolio concentrates investments around a single maturity point. For example, a portfolio consisting entirely of 5-year bonds. This structure has high sensitivity to rate changes at that specific maturity, making its performance highly dependent on the 5-year point of the curve.

A barbell portfolio splits investments between short-term and long-term maturities, avoiding the middle. For instance, half in 2-year bonds and half in 10-year bonds. This structure benefits when the curve flattens (long rates fall relative to short rates) and often provides higher convexity. However, it is vulnerable to a steepening move.

A ladder portfolio distributes investments evenly across a range of maturities (e.g., bonds maturing each year from 1 to 10 years). As the shortest bond matures, proceeds are reinvested at the long end. This strategy provides liquidity, reduces reinvestment risk, and performs steadily across various curve environments but rarely offers outperformance.

Active Strategy 1: Riding the Yield Curve

Riding the yield curve (or rolling down the yield curve) is a common strategy when the curve is upward-sloping and you expect it to remain stable. It involves buying a bond with a maturity longer than your intended holding period. As time passes, the bond's maturity shortens, and assuming a stable curve, it is priced at a lower yield (and higher price) corresponding to a point further down the curve.

Consider a steeply sloped curve where the 5-year yield is 4% and the 4-year yield is 3.5%. You buy the 5-year bond and plan to hold it for one year. If the curve remains unchanged after one year, your bond will now be a 4-year bond priced at the prevailing 4-year yield of 3.5%. The capital gain from this "roll down" enhances your total return beyond the bond's initial coupon. The primary risk is that an unexpected upward shift in rates can erase this gain.

Active Strategy 2: Positioning for Curve Shifts with Duration and Key Rate Duration

To actively bet on curve movements, you need more precise tools than just overall duration, which measures sensitivity to a parallel shift. Key rate duration measures a portfolio's sensitivity to changes in the yield at a specific maturity point (or "key rate"), holding all other rates constant.

This allows for targeted positioning. If you forecast a non-parallel shift—such as a short-end steepening where 2-year yields rise more than 10-year yields—you would structure your portfolio to have low exposure (low key rate duration) to the 2-year point and higher exposure to the 10-year point. This might involve underweighting short-term bonds and overweighting long-term bonds relative to your benchmark. By adjusting key rate durations, you can construct a portfolio that profits from your specific view on which part of the curve will move.

Active Strategy 3: Butterfly Trades

A butterfly trade is a more advanced, duration-neutral strategy designed to profit from changes in the curvature of the yield curve—specifically, whether the middle of the curve cheapens or richens relative to the wings. The most common structure is a bullet-barbell trade.

In this trade, you take a long position in a barbell (short and long maturities) and a short position in a bullet (intermediate maturity), or vice versa. The durations are balanced so the portfolio has zero net exposure to a parallel shift.

• If you execute a long barbell / short bullet trade, you are betting on increased curvature. You profit if intermediate yields rise relative to short and long yields (the curve becomes more humped).
• Conversely, a short barbell / long bullet trade bets on reduced curvature. You profit if intermediate yields fall relative to the wings (the curve flattens in the middle).

For example, if you believe the 5-year yield is too low compared to the 2-year and 10-year, you would sell the 5-year bullet and buy a combination of 2-year and 10-year bonds (short barbell / long bullet). If your view is correct and the 5-year yield rises, the price of your short position falls, generating a profit.

Common Pitfalls

1. Misinterpreting Riding the Yield Curve: This strategy critically depends on a stable, upward-sloping curve. The most common error is employing it when the curve is flat or inverted, or when expecting major rate hikes. In such scenarios, the price depreciation from rising yields can easily outweigh the roll-down benefit.
2. Ignoring Convexity in Barbell vs. Bullet Comparisons: A barbell structure typically has higher convexity than a bullet with the same duration. When comparing them, failing to account for this means you are not comparing true risk-adjusted returns. The barbell will outperform in volatile rate environments due to this convexity advantage, which isn't a free lunch—it is often paid for via a lower yield.
3. Forgetting to Neutralize Duration in Butterfly Trades: A butterfly trade is meant to be a pure play on curve curvature, not direction. A frequent mistake is constructing the trade without ensuring the net duration is zero. If you are long the barbell and short the bullet but have positive net duration, you are inadvertently taking a bullish bet on rates, which will dominate your P&L if a parallel shift occurs.
4. Overlooking Liquidity and Transaction Costs: Many sophisticated curve strategies involve multiple legs (long/short positions at different maturities). Executing these trades incurs bid-ask spreads and transaction costs that can erode the theoretical profit. This is especially true for less liquid points on the curve, such as very long maturities or off-the-run securities.

Summary

• Your fixed income strategy must start with a view on the yield curve, which reflects market expectations for growth, inflation, and policy.
• Bullet, barbell, and ladder portfolios provide baseline exposures with different sensitivities to curve shifts, steepening, and flattening.
• Riding the yield curve is a powerful carry strategy in a stable, upward-sloping environment but carries significant risk if rates rise.
• Active positioning requires moving beyond standard duration to key rate duration, which allows you to target specific maturity points for non-parallel shifts.
• Butterfly trades are duration-neutral strategies to exploit changes in the curvature of the yield curve, most commonly executed as a bullet versus barbell position.