parallel shift in the yield curve means: An economic shift where the rate of change on all maturities changes by the same amount. The T-bill for three months increases by 100 basis points. If the 3-month rate rises 100 basis points, the rates on the 30-year, 6-month, 5-year and 10-year maturities all increase 100 basis points. Related: Non-parallel Shift in yield curve (in Stock Market Dictionary)