AT&T (NYSE:T) has installed fiber to an additional 450-plus multi-tenant office buildings across the San Francisco metro area, making fiber-based broadband services available to more than 16,000 business customer locations.The effort is part of AT&T's Velocity IP Plan, a three-year investment plan to expand and enhance the company's wireless and wireline IP broadband networks, including deploying its fiber network to an additional 1 million business customer locations in its wireline service area by year-end 2015.