A

parallel shift in the

yield curve is a shift in the yield curve - that is, a change in yields - in which all

maturities change by the same number of

basis points.

In other words, if the yield on the 3 month

T-bill increases 100 basis points

*(or one percent)*, then the 6 month, 1 year, 5 year, 10 year, 20 year, and 30 year rates will all increase by 100 basis points as well.

Some

academic studies has estimated that over 90% of all shifts of the yield curve are indeed parallel.

See also: Non-parallel shift in the yield curve