Residents and representatives from Birmingham City Council joined to celebrate the milestone event.
Once complete, Allegro will offer 603 high quality apartments designed exclusively for rent, ranging from studios to three-beds in size.
A total of 307 fully furnished and stylish apartments have been completed over two blocks, while the final phase of the development will see a 27-storey tower delivered this autumn.
Penthouses come with their own private sky gardens with views of the evolving Birmingham skyline but all residents will have access to landscaped podium gardens and the 5,000 sq ft residents' hub. At the hub, residents will find a hotel-style concierge, members' club-style lounge, state-of-the-art wellness centre and parcel lockers.
Allegro was Birmingham's first significant build-to-rent scheme and acted as a catalyst for further BTR activity in the city. LaSalle Investment Management forward funded the development on behalf of one of the UK's largest pension funds in a £105m deal.
Andrew Stanford, Head of Residential Asset Management at LaSalle Investment Management, said: "Allegro has been designed from the ground up to foster a vibrant community of like-minded renters who we hope will see the whole building and not just their apartment as their home. It provides a wholly different renting experience than the offer of buy-to-let landlords. People deserve better and we will meet their needs."
Allegro marks phase one of Nikal's Exchange Square project and sits directly opposite where the new HS2 terminal will be.
Speaking at the event, Ian Ward, Birmingham City Council leader said: "Allegro symbolises the face of Birmingham, quite literally heightening the city centre. It will give developers and investors real confidence and will provide much needed homes for young professionals and new families.
"Allegro offers high quality homes that are sorely in demand and will help Birmingham attract and retain the right talent as Birmingham reinvents itself. Schemes such as this will help build a bright future for all the Birmingham."
