Allen & Overy's US arm has advised on the $930m (£585m) sale of Boston's iconic John Hancock Tower to a US real estate investment trust, reports The Am Law Daily.

Boston Properties, which is headed up by US publishing billionaire Mortimer Zuckerman, purchased the tower in a deal comprising $290m (£182m) in cash and $640m (£403m) in assumed debt.

A&O's New York managing partner Kevin O'Shea (pictured) led the magic circle firm's team on the deal after advising Normandy Real Estate Partners and Five Mile Capital Partners on their purchase of the tower just 18 months ago for $20m (£12.6m) in cash and the assumption of $640m in debt.

"From cradle to grave in two years? Nobody expected that," said O'Shea. "We expected the world was going to end back then."

US firm Goodwin Procter advised Boston Properties with a team led by partner James Broderick.

The sale of the tower will be seen by many as a sign that the commercial real estate market is ready for a true rebound.

O'Shea began advising US funds Normandy and Five Mile well before the 2009 deal, helping them accumulate debt from the tower's prior owner and position themselves as key creditors in the event of that owner's potential default.

That owner, Broadway Partners, missed a debt payment in January of last year, and the Normandy/Five Mile group declared Broadway in default and then won the tower at auction.