bp

basis point

Dimensionlessexact by definition

A basis point is one hundredth of a percent, exactly 1e-4. It is finance's unit for interest rates, yields and fees, where a quarter point rate move is 25 basis points, and it also turns up in engineering tolerance and drift specifications. The factor is exact by definition.

1 bp 0.0001 —
Where the unit came from

The unit exists to remove an ambiguity rather than to shorten a number. A rate that moves from 4 percent to 5 percent has risen by one percentage point and by 25 percent of its former value; saying it rose 100 basis points can only mean the first.