BoA is to take over 250,000 sq ft, half the space that will be available in CSFB's new building, 5 Canada Square, which is due for completion in 2002. With about 1.2m sq ft owned or leased, CSFB is Canary Wharf's biggest occupant and the deal with Bank of America would be the first major sublet in the Docklands office centre.