Initial public offerings have been doing extremely well lately, bringing to mind the excesses of the tech bubble in the late 1990s. Shares in Chinese toymaker Pop Mart International Ltd. jumped as much as 112 per cent in their debut Friday, after home-rental platform Airbnb Inc. closed 113 per cent above its IPO price in New York. JD Health International Inc. surged 56 per cent in its debut Tuesday while DoorDash Inc. soared 86 per cent in on Wednesday.