Frontier Estates and Opus Land - joint developers of The Green in Solihull - have sold their stake in the 54-acre, mixed use scheme for a figure approaching £4 million.
The pair's interest has been acquired by the scheme's funder, Prudential, which will now be developing the site independently.
The complex was acquired some four years ago in a £40 million deal - at the time the biggest office development transaction outside the capital.
Since then infrastructure work has been completed, planning permission for 350,000 sq ft of office development granted and land sales to Audi, Sunrise and DeVere concluded.
Richard Smith of Opus Land said: "We have transformed the former TRW site into a dynamic place to do business with the completion of three land sales to create the flagship Audi regional centre, the Sunrise Senior Living care home for the elderly and the £20 million De Vere hotel and leisure complex with a pub, cafe and restaurant.
"Now that vehicle and pedestrian access both to and within the site has been facilitated, the extensive landscaping scheme finished and final touches such as the entrance water feature added, we are now ready to hand the project on so its full potential can be realised."
The development firms say that with an end value of over £100 million, The Green is one of a new generation of business locations - a sustainable, thriving commercial centre which also provides first class facilities to the local community of which it forms an integral part. Some 2,000 jobs will result from the diverse mix of activity on site.
Meanwhile property and construction consultancy Wakemans is working with Castlemore Securities and its dedicated residential and regeneration arm, Spring UR, on a landmark £50 million mixed use scheme in Mere Green, near Sutton Coldfield.
Spring UR will develop retail premises and residential accommodation on a three-acre brownfield site at the corner of Lichfield Road and Mere Green Road.
Wakemans has been appointed project manager on the development.
The aim is to regenerate the area by creating a town centre for Mere Green, giving it a focus and broadening its appeal to local residents and visitors, while maintaining its character.
A landscaped "village square" will be surrounded by 25 shops, linked to restaurants and cafes. Meanwhile, 152 apartments will be built in the three upper storeys.
Wakemans is currently out to tender for the demolition work, which is due to start at the beginning of April.
The main contract will be tendered in March, with construction starting in July. The scheme is scheduled for completion in 2010.
