Figured this out. On the devices you want to sync bookmarks with that differs from the primary iTunes account, sign out from iTunes on the device on both. Go to system settings and iBooks and disable syncing bookmarks on both devices. Then force quit iBooks on both devices, go back into iTunes sign into an alternative iTunes account on both devices. Turn back on bookmark syncing on both devices then open iBooks and it should ask if you want to change syncing with this account (something like that, not meant to be verbatim). Select yes or ok or whatever the option is that means yes. Test in iBooks. Open a book that you have on both devices and bookmark a page then open the same book on another device and validate it opens the same page you bookmarked. Now you can safely sign out of the alternative iTunes account and back into your primary account on both devices and it will continue to sync to the alternative account for iBooks. ================================================================ Original post: My wife and I share one Apple ID for Apps and iTunes Match but it's a pain in the arse when using iBooks between my iPhone and iPad and her iPhone and iPad when reading books in iBooks. We'll often read the same books at a different pace and we either need to only let one of us sync bookmarks and the other manually find the place they left off on their one device when using the other or we both can't sync between anything. Is there a way I'm missing to select just iBooks to sync bookmarks between a different Apple ID? We use a different Apple ID for iCloud backups on my wife's iPhone and iPad so I'm hoping there's a way to do the same but I have searched online and through all the settings I could find but cannot figure out a way.