Probably Lippert Industries. They manufacture the Thomas Payne furniture line which is what Keystone uses in most of their "mid/high level lines"...
https://www.lci1.com/thomas-payne
ADDED: Chances are, if you turn it over and pull the dust cover from the bottom, you can access the two or three nuts that hold the arm in place. Tighten them, restaple the dust cover and turn the recliner back over on its feet. If it was secured to the wall, you might consider resecuring it. Some people do, some don't.