Fetching details from the dictionary...
joint sponsorship (of an event); cosponsorship; joint hosting
二社が共同で技術会議を共催する。
Two companies will jointly sponsor a technology conference.
市と地元商店街の共催で文化祭が開かれた。
A cultural festival was held through the co-sponsorship of the city and a local business association.
大学とNPOがチャリティコンサートを共催した。
The university and an NPO co-sponsored a charity concert.