According to the Korea Herald, LG Display started to develop a foldable OLED display specifically for Apple. LG Display is collaborating with LG Innotek who will develop a flexible printed circuit board for the display.
It is estimated that LG display will not be able to produce such a foldable OLED until 2020. This may be a bit late for Apple as Samsung Electronics hopes to release its first foldable phone in 2018. But Apple is very keen on creating a second source for its OLEDs as it does not want to rely on Samsung Display alone.
Business Korea also suggests that Apple does not want to share its foldable phone plans with Samsung Display as it fears the design and ideas may leak to SDC's parent company Samsung Electronics.