Which studio co-developed PUBG Mobile with PUBG Studios?

LightSpeed Studios co-developed PUBG Mobile with PUBG Studios.

LightSpeed Studios, a Tencent Games subsidiary formerly known as LightSpeed & Quantum Studio, handled major development work on the mobile adaptation alongside PUBG Studios. The partnership combined PUBG’s original creators and game-design expertise with Tencent’s mobile-development resources and experience with large-scale online games.

PUBG Mobile was built from the PC and console version but required substantial technical adaptation. The teams optimized Unreal Engine 4 for smartphones, adjusted controls for touchscreens, and worked to preserve the battle royale’s large maps, vehicle systems, weapons, and multiplayer structure on less powerful hardware.

The mobile project followed two China-focused prototypes released in February 2018: Exhilarating Battlefield, made by LightSpeed & Quantum, and Army Attack, made by TiMi Studio Group. The internationally released PUBG Mobile descended from the LightSpeed-led version, which is why TiMi is a plausible but incorrect answer to this question.