Even though the building had not officially opened, Comcast office workers began moving in early December 2007, ahead of the scheduled completion in March 2008. The Comcast Center officially opened on June 6, 2008. A study sponsored by Comcast and Liberty Property Trust said the construction of the Comcast Center created 17,200 jobs and generated US$2 billion of economic activity for Pennsylvania. Despite opposition by other building owners to construction of the Comcast Center, by the time most space in the Comcast Center had been leased vacancy rates in Center City offices were falling and rents were rising. Even HRPT Properties Trust had leased 70 percent of the space Comcast vacated by 2007. The predictions by opponents did not occur mainly because Comcast ended up leasing 89 percent of the building and the offices for the Comcast Center's second-largest tenant, Citizens Bank of Pennsylvania, were new to the city.