Five months after the Shard skyscraper in London celebrated its near-completion with a laser show and party attended by Prince Andrew, it still hasn't completed a lease for any of its 590,000 sq ft of office space.

But a few miles away, in the city's insurance district, another new development scheduled to open in 2014 is doing much better. The Leadenhall Building, nicknamed "The Cheesegrater" for its distinctive wedgelike design, is now 51% preleased after securing Aon and Amlin as tenants.