Searching the existing questions around about the transferring of android app from one dev account to another but haven't found anyone mentioned about the app Statistics and Ratings & Reviews.
Anyone have already transferred app? and what happens to your app Statistics and Ratings & Reviews
At least in this article about Google's "outrageously simple process" to transfer an app to a different Google Play Developer account it's mention that if Google would not be offering this service, you would lose "every single download, rating, and review in the Google Play Store", which implies that this information indeed is maintained.
Note that this answer also refers to the above article as the "old method" to transfer an app "without loosing download count or rating". However, I cannot imagine that the "new method" would suddendly not transfer your app's ratings. The Android Developer Help instructions still seem valid to me.
