Animation Studio A-1 Pictures have recently taken over the animation and planning production from Studio 3Hz Co., Ltd. As a result Studio 3Hz’s buisness will continue under A-1 Pictures, and “Sword Art Online Alternative: Gun Gale Online II,” which is being produced by Studio 3Hz, will continue to be produced by the same staff as before.
3Hz Inc. animation studio was established by ex-Kinema Citrus animators. Yuichiro Matsuka founded the studio in March 2013. The company is referred to as Studio 3Hz on anime staff credits. The studio has produced numerous series & film like Blackfox (Movie), Dimension W(co-produced with Studio ORANGE), Flip Flappers, Sword Art Online Alternative Gun Gale Online, The Devil Is a Part-Timer!! and many more.
Source: A-1 Pictures X/Twitter Account