Vistra Group Holdings (BVI) Limited acquired 9.99% stake in Mainstream Group Holdings Limited (ASX:MAI) from Byram Johnson, Martin Smith, John Plummer on June 9, 2021. Vistra Group Holdings (BVI) Limited completed the acquisition of 9.99% stake in Mainstream Group Holdings Limited (ASX:MAI) from Byram Johnson, Martin Smith, John Plummer on June 9, 2021.