Momentum Inc. (Head office: Minato-ku, Tokyo; President and Representative Director: Kohei Hosoi) will hold a webinar with HAKOBUNE Inc. (Head office: Shinagawa-ku, Tokyo; Representative: Yuki Haruna) on Thursday, May 21, 2026, titled “A Must-See for Agencies: Failure Cases and Keys to Success in Using External Partners: Methods for Moving Beyond ‘Throwing Everything Over the Fence’ and Building Trust.” The webinar will address common problems that arise when advertising agencies begin using external partners, such as operations becoming a black box and unstable ad delivery quality. Based on failure cases often seen in the field, the session will share proper division-of-labor rules for achieving results, the first steps for using external partners, and methods for managing ad delivery quality when working with outside partners. It will also explain how to build an organization that moves beyond simply outsourcing everything and strengthens client trust. The seminar is recommended for managers who want to prevent operational black-boxing caused by full delegation, people who want to improve unstable ad delivery quality caused by overreliance on partners, those who want to break the negative outsourcing cycle in which knowledge does not remain in-house, and those who want to build a strong division-of-labor structure that earns client trust. The webinar will be held online via Zoom. The live session will take place on Thursday, May 21, 2026, from 11:00 to 12:00. Archive sessions will be streamed on Wednesday, May 27, and Thursday, May 28, 2026, from 11:00 to 12:00. The event is hosted by HAKOBUNE Inc. and Momentum Inc. Registration is available at: https://www.m0mentum.co.jp/seminar/260521_seminar. Speakers include Yuki Haruna, Representative of HAKOBUNE Inc. In the financial sector, he has improved CPA while managing advertising operations at a scale of 100 million yen per month, and in the beauty sector, he has generated results through cross-media operations. In a