Parallel and Non-parallel Shifts in Yield Curve
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Parallel Shift
Rates across the maturity spectrum change by a constant amount and the slope of the yield curve remains consistent.
Non-Parallel Shifts
- Twist: The slope of the yield curve becomes flatter (the spread between short and long term yields narrows) or steeper (the spread between short and long term yields widens).
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Butterfly: Change to the curvature of the yield curve.
Positive butterfly: The yield curve goes loses some of its "hump" and becomes straighter.
Negative butterfly: The yield curve takes on more of a hump and ceases to look similar to a straight line.
