Their sales over the past few weeks have pushed up nominal yields far more quickly than the BoJ expected.
过去几周的卖出量迅速推高了名义收益率，其速度超出日本央行的预期。
英语百科
Nominal yield
The coupon rate (or nominal rate or nominal yield) of a fixed income security is the (annualized) amount of the coupon, which is a fixed percentage of the par value. Unlike current yield, it does not vary with the market price of the security. The coupon rate is typically stated in the name of the bond, such as "US Treasury Bond 6.25%".