It has been a torturous process and there may still be twists and turns to come, but a massive office complex in Madrid is on the verge of becoming the largest single real estate asset ever sold.

Ciudad Santander is the 4.3M SF headquarters of Spanish bank Santander. It has been mired in bankruptcy and restructuring proceedings for almost a decade, but this summer it is expected to be sold for €2.7B to €2.8B ($3.2B to $3.3B).

The current record for a single asset is the $2.8B paid for the GM Building in New York in 2007.

Ciudad Santander is a different prospect — it is spread over 340 acres and includes a grove of 1,000-year-old olive trees, a championship golf course and a nursery that can accommodate 550 children.

Three groups are battling it out for control of the building: Kuwaiti-backed fund AGC, which has bid €2.7 to €2.8B; a consortium of Madison International, hedge fund Global Asset Capital and one of the current owners, U.K. investor Glenn Maud, which has bid around the same level; and one of the other equity holders, Robert Tchenguiz, who is attempting a refinancing with more than €2B of debt provided by JP Morgan.

The special purpose vehicle that owns the building is in Spanish bankruptcy, and the court must decide which option to proceed with. A decision is due this quarter, or early next quarter, according to Spanish newspaper Voz Populi. AGC is seen as the front-runner, the newspaper said.

The transaction has been a complex mess from the moment it was finalised. Maud and his then-joint venture partner, Irish entrepreneur Derek Quinlan, bought the building for €1.9B, with the deal completing the day after Lehman Brothers collapsed.

The pair bought the building using just €25M of equity, court documents showed, a 98% loan-to-value ratio. A consortium of senior lenders provided €1.6B, and Royal Bank of Scotland provided €200M of junior debt plus a €75M equity loan.

Given the timing of the deal, that meant it fell into negative equity almost immediately. Tchenguiz, backed by Abu Dhabi fund Aabar, bought the junior debt and Quinlan’s equity in 2010 to try to take control of the property, and the pair have been locked in a legal battle with Maud for control since 2011.

In 2015 the SPV went into bankruptcy protection. The amount repayable has racked up as a result of interest on the loans, and now stands at about €2.7B.

In spite of this complexity, the building has one extremely valuable facet — the lease to occupier Santander. It ran to 40 years at the time of the deal, with rental uplifts of at least 2.2% or the rate of inflation, whichever is higher. In the first year Santander paid rent of €83M. It will pay at least €2.65B over the life of the lease.