As well as considerable investment in the playing squad that delivered last season’s record-breaking promotion to the second tier under Chris Davies, Blues’ owners have poured between £20m and £25m into improving the stadium.
There are also plans to move to a new 62,000 seater home ground as part of a £3bn regeneration of a new Sports Quarter in the city.
It is hoped that new stadium will be open by 2030.
“This transaction is another important milestone for Knighthead and Birmingham City Football Club,” Wagner said of SCL’s move to full ownership.
“Transformation has taken place across every aspect of the club’s operations since our initial investment and it’s just the beginning.
“Later this month we will unveil our new stadium design which will be at the heart of East Birmingham’s Sports Quarter.
“The ambition for our club is to be a beacon of excellence for Birmingham on the global stage. The journey to deliver this is well under way.”
Birmingham are ninth in the Championship table after 14 games, two points outside the play-off places.