Basis point

Basis points are used as a convenient unit of measurement in contexts where percentage differences of less than 1% are discussed.

It is common practice in the financial industry to use basis points to denote a rate change in a financial instrument, or the difference (spread) between two interest rates, including the yields of fixed-income securities.

Expense ratios of investment funds are often quoted in basis points.

The same unit is also (rarely) called a permyriad, literally meaning "for (every) myriad (ten thousand)".

(It can be regarded as a stylized form of the four zeros in the denominator of "⁠1/10,000⁠", although it originates as a natural extension of the percent % and permille ‰ signs).