Bond Portfolio Strategy — Diversification and Yield Optimization

Why a Bond Portfolio Is Necessary

Problems with single-bond investing:

• Maturity concentration risk: large maturities clustering at one point in time
• Interest rate risk: reinvestment risk if everything is short-term
• Liquidity problem: hard to convert to cash if holding only long-term bonds

The portfolio approach systematically diversifies these risks.

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The Three Core Bond Portfolio Strategies

1. Ladder Strategy

Structure

Allocate equal amounts across multiple maturities

• Example: 20% each in 1-year, 2-year, 3-year, 4-year, 5-year bonds

How it works — 1-year bond matures → recover principal → reinvest in 5-year bond → always maintain a 1–5 year portfolio

Advantages

• Automatic adaptation to interest rate changes (cost averaging)
• Regular cash flows secured
• No complex judgments required

Disadvantages

• Misses short-term yield opportunities during sharp rate rises
• Limits gains on long-term bonds during sharp rate falls

2. Barbell Strategy

Structure

Concentrate only on short-term (1–2 years) + long-term (10–30 years)
Hold no intermediate maturities

• Example: 50% short-term + 50% long-term

Advantages

• Short-term: maintain liquidity + rapid reinvestment when rates rise
• Long-term: maximize capital gains when rates fall

Disadvantages

• Long-term bonds suffer if intermediate-term rates rise
• More volatile than the ladder strategy

3. Bullet Strategy

Structure

Concentrate maturities at a specific target date

• Example: planning to buy a house in 5 years → concentrate on 5-year bonds

Advantages

• Optimized for a specific funding target
• Maximizes returns if rate forecast is accurate

Disadvantages

• Reinvestment yield falls if rates are low at the target date
• No diversification benefit due to single-point concentration

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Stock-Bond Allocation Principles

The Traditional 60/40 Portfolio

Stocks 60% + Bonds 40%

Historical performance (1990–2020)

• Average annual return: ~8–9%
• 2022: rapid rate hikes pushed both asset classes lower (stress test)

Modern adjusted allocation

• Adjust flexibly based on risk tolerance
• 100 minus age = stock allocation (traditional rule of thumb, for reference)

Bond Allocation Guide by Age

Age Group	Bond Allocation	Rationale
20s–30s	10–20%	Long investment horizon, higher risk tolerance
40s	20–40%	Transitioning to a balanced portfolio
50s	40–60%	Strengthening capital preservation
60s+	50–70%	Prioritizing stable cash flows

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Bond Portfolio Rebalancing

When Rebalancing Is Needed

• Time-based: periodically every 6 months or 1 year
• Threshold-based: when the allocation drifts more than 5 percentage points from target
• Event-based: when a turning point in the interest rate cycle is identified

Executing a Rebalance

Example:

Target: Stocks 60% / Bonds 40%

Current: Stocks 68% / Bonds 32% (after equity rally)

• Sell 8% of stocks, buy 8% of bonds to restore target
• Be mindful of taxes on capital gains triggered in the process

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Managing Duration in a Bond Portfolio

Set target duration

• Expecting rising rates → shorten duration (increase short-term bond weight)
• Expecting falling rates → extend duration (increase long-term bond weight)
• Uncertain environment → neutral position

Duration calculation

• Portfolio duration = weighted average of individual bond durations
• Example: 50% in 2-year bonds + 50% in 10-year bonds = 6-year duration

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A Practical Portfolio Example

40-year-old professional, $100,000 bond portfolio

Applying the ladder strategy:

• Short-term (1–2 years): government bonds $20,000

• Medium-term (3–5 years): government bonds $30,000

• Medium-long-term (7 years): high-grade corporate bonds (A+ rated) $20,000

• Long-term (10 years): government bonds $20,000

• Inflation-linked bonds (TIPS): $10,000

• Expected return: 3.5–4.5% per year (varies with interest rate environment)

• Duration: approximately 5.5 years

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Key Takeaways

Ladder: diversification and automatic adaptation / Barbell: short-term liquidity + long-term gains / Bullet: concentrate on a target date 60/40 portfolio: its limits were tested in 2022 by rapid rate hikes → flexible adjustment required Duration management: expecting rate rises → shorten; expecting rate falls → extend