What is Yield to Worst (YTW) — The Conservative Bond Standard?
Mathematical Foundation
Laws & Principles
- The Call Premium Offset: Issuers sweeten the call with a premium (e.g., $1,020 instead of $1,000 par) to partially offset the investor's capital loss. For premium bonds, this rarely makes YTC compete with YTM.
- Premium Bond Rule: If you buy at a premium (e.g., $1,080) and the bond is called at $1,020, you suffer an accelerated capital loss in a short window. YTC is almost always the driving YTW for premium bonds.
- Discount Bond Rule: If you buy at a discount (e.g., $900), early call at $1,020 massively accelerates your gain. The issuer will not call — YTM drives the YTW for discount bonds.
Step-by-Step Example Walkthrough
" You buy a $1,000 par bond for $1,050. Coupon: 5% ($50/yr). Maturity: 10 years. Call: issuer may call at $1,020 in 4 years. "
- YTM: ($50 + ($1,000 − $1,050)/10) / (($1,000 + $1,050)/2) = $45 / $1,025 ≈ 4.39%
- YTC: ($50 + ($1,020 − $1,050)/4) / (($1,020 + $1,050)/2) = $42.50 / $1,035 ≈ 4.11%
- YTW = min(4.39%, 4.11%) = 4.11% — driven by YTC