On Oct 2, トラストアップ株式会社 submitted the Large Shareholding Report to Ministry of Finance to disclose its 7.77% ownership of the shares in $AltPlus (3672.JP)$.
Source: Edinet Announcement
What is the 5% shareholding reporting system?
Shareholders with holding ratio exceeding 5% must submit a Large Shareholding Report within five business days from that day. If the holding ratio increases or decreases by 1% or more after submitting a Large Shareholding Report, the holder must submit a Change Report within five business days from that day.