Definition of 'Yield Basis'
A method of quoting the price of a fixed-income security as a yield percentage, rather than in dollars. This allows bonds with varying characteristics to be easily compared.
Investopedia explains 'Yield Basis'
Unlike stocks, which are quoted in dollars, most bond quotes include a yield %. For example, Corp. ZZZ is listed with a 6.75% coupon, a Sept 04/20 maturity, has a dollar value of 94.00 and a yield of 9%.
This bond quote tells a bond trader that the bond is currently trading at a discount because its yield basis (9%) is greater than its coupon rate (6.75%). A bond trader could then compare the bond to others within a certain industry.