NEW YORK—Midtown moved up two places to rank as the world's third-most expensive office market, surpassing Moscow and Tokyo, according to research unveiled today by Cushman & Wakefield.

The firm's annual Office Space Across the World global ranking, notes that occupier activity in New York City was powered by large deals with total take-up reaching a staggering almost 33 million square feet in 2014—the highest level in more than 15 years. Activity was bolstered by the return of the 'mega-deal', as 28 new deals in excess of 100,000 sq ft were completed. Robust leasing activity pushed vacancy rates to single digits for first time since July 2012.

Midtown space brought rents that averaged $131 per square foot annually, while Hong Kong's CBD brought $184, and London's West End tenants paid $284 for the same amount of space.