CFA Level II ExamFixed IncomeMedium

An analyst is comparing two option-free bonds, Bond A and Bond B. Bond A has a modified duration of 5.5 years and a convexity of 45. Bond B has a modified duration of 6.0 years and a convexity of 30. If interest rates are expected to decrease significantly, which bond is likely to experience a larger price increase, and why?

  1. ABond A, due to its higher convexity.
  2. BBond B, due to its higher modified duration, despite its lower convexity.
  3. CBond B, due to its higher modified duration.
  4. DBond A, due to its lower modified duration and higher convexity.
Show answer & explanation

Correct answer: A. Bond A, due to its higher convexity.

When interest rates decrease significantly, both duration and convexity contribute positively to bond price changes. While Bond B has a higher duration, Bond A's significantly higher convexity will likely lead to a larger price increase, as convexity becomes more impactful with larger interest rate changes and amplifies price gains when rates fall.

Why the other options are wrong

  • B. The higher duration of Bond B would be beneficial, but its lower convexity would temper the price increase compared to Bond A's higher convexity during a significant rate drop.
  • C. While duration is important, the impact of significantly higher convexity on price gains during large rate drops is crucial.
  • D. Lower modified duration would typically lead to a smaller price increase, but higher convexity is the dominant factor here.

Convexity and Price Sensitivity

Convexity measures the curvature of a bond's price-yield relationship, indicating how duration changes with interest rates.

  • Positive convexity is desirable, especially for large interest rate changes.
  • When rates fall, higher convexity leads to greater price appreciation.
  • When rates rise, higher convexity leads to smaller price depreciation.

Memory trick: Duration Drives Direction, Convexity Curbs Curves.

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