Legal & General (L&G) has entered into a joint venture (JV) with Welsh developer Rightacres Property.
The financial services company will invest £400m into the Central Square regeneration scheme for Cardiff City Council.
The 12-acre mixed-use development is to comprise one million sq ft of space in the city centre.
The first phase of the project includes the development of two buildings, the 150,000 sq ft BBC Wales HQ and the 135,000 sq ft One Central Square office development.
One Central Square is already part pre-let to national law firm, Blake Morgan, and is due for completion in January 2016.
Further project phases include a mix of commercial and residential buildings.
The deal is the second project to be delivered through L&G's Regeneration Investment Organisation (RIO) partnership.
Chancellor of the Exchequer, George Osborne, said: "Today we see a major vote of confidence in the Welsh economy with a new partnership between Legal & General and Rightacres. The £400 million regeneration project which will be delivered through this partnership is fantastic news for working people across Wales and will help transform Cardiff's city centre creating 10,000 new jobs."
Laura Mason, Director of Direct Investment at L&G Capital, said: "We look forward to working closely with our new development partners and Cardiff City Council to deliver this major project and attract further investment to the area."
Paul McCarthy, Chief Executive of Rightacres, added: "Having a funding partner like Legal & General alongside us in Central Square will maintain the momentum we have been building around the scheme."
(LM/CD)
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