Strong investor demand has supported an increase in the issuance of long - dated private sector debt in hong kong . low interest rates induced demand for structured products offering yield enhancement features such as step - up coupons and call options 低利率环境使附有提高收益特点的特别结构债券的需求上升,附有步升票面息率及赎回选择权的债券都是其中的一些例子。