We had the ability to sync your stocks between several iOS devices via Apple's iCloud Drive system. However the latest Apple changes to its system (including iOS 11) made us disable our iCloud sync feature due to some issues. But no worries: the iCloud sync feature will be back really soon - in one of the nearest updates. Until then, I'm afraid you'll need to make changes manually. Sorry about that.
Thanks for understanding, please stay tuned for updates.