Rockpoint and the Abu Dhabi Investment Authority have won vital breathing space on a £336m loan that was scheduled to mature tomorrow.

The US private equity firm and the world’s largest sovereign wealth fund have secured a two extension on the debt secured against the 600,000 sq ft Devonshire Square estate in the City, removing the probability of an imminent sale.

The debt has been extended from 20 October to 23 April 2013. The estate comprises 12 buildings just east of Liverpool Street Station, which was bought by Rockpoint for £410m in October 2006. It then sold a 25% stake in the building to ADIA for £110m. The last valuation of the building was just £267m.

The drop in value is primarily due to the occupational situation at the building. Insurance company Aon, which accounts for 46% of the £20m annual rent roll, is set to move out in 2014 and take space at British Land and Oxford Properties’ Cheesegrater scheme on Leadenhall Street.

As part of the loan extension, the borrowers have put up £3m to secure some tenancy agreements and help regear leases.

One tenant has agreed to a new 25 year lease, which increases rental income by £300,000 a year.

As part of a business plan, Rockpoint and ADIA need to either refinance the loan or sell the property by April 2013. Morgan Stanley Mortgage Servicing, which manages the loan and agreed the extension after a year of talks, said it did not think marketing the property at the current time was the best solution.

The loan was provided by Morgan Stanley and then securitised, meaning that investors bought bonds secured against the income from the property.