Stealth movement is it 2/3 speed per overland movement or full speed during combat?

@JeremyECrawford Stealth movement speed continues to be a question; is it 2/3 speed per overland movement, or full speed during combat?

— JH (@SporkKeeper) May 3, 2016

Stealth imposes no movement reduction in combat. #DnD https://t.co/ywBMO2zUaq

— Jeremy Crawford (@JeremyECrawford) May 9, 2016