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I-spread

Bond and yield

Wikipedia contributorsAdapted for Fathomly · View authors
1 min read
Source updated June 20, 2026

The Interpolated Spread, I-spread or ISPRD of a bond is the difference between its yield to maturity and the linearly interpolated yield for the same maturity on an appropriate reference yield curve. The reference curve may refer to government debt securities or interest rate swaps or other benchmark instruments, and should always be explicitly specified. If the bond is expected to repay some principal before its final maturity, then the interpolation may be based on the weighted-average life, rather than the maturity.

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This article is adapted from the Wikipedia article “I-spread”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

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Z-spread

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