Xiaomi-linked companies have faced increased scrutiny by China’s regulators, with some pausing planned initial public offerings after being questioned about their close relationship with the smartphone giant. Smart mattress maker 8H, intelligent lighting company Yeelight and commercial operating system maker Shanghai Sunmi Technology have each shelved IPO plans in recent months, according to documents and Chinese media reports. Those moves have come after they were questioned by China’s regulators as being part of [Xiaomi’s](//www.ft.com/stream/cad8c728-c0fc-4b92-af83-50e21875eaa9) so-called “ecosystem companies”, a vast array of groups that the smartphone seller has either directly invested in or has made commercial arrangements with. The strategy has...