IHS estimates that sales of mobile flexible AMOLED displays reached about $2 billion in Q2 2017 - more than double compared to Q2 2016 ($886 million).
Samsung still commands this market - IHS says that SDC had a market share of 98.3% in the second quarter. The second flexible OLED market is LG Display which is reportedly still struggling with yield and quality issues at its new E5 flexible OLED line and so has a low capacity. LGD will hopefully soon increase its capacity dramatically. Chinese OLED makers are now initiating flexible OLED production as well.