There is guidance available in Cite Them Right Online on how to reference company data. See attached a link to the Cite Them Right guide via Library Search.

You would use the format shown here in the Cite Them Right Harvard style: 

Reference:
Bureau van Dijk (2012) 'BT Group plc company report'. Available at: http://fame.bvdep.com (Accessed: 5 January 2013).

In-text citation: 
Bureau van Dijk (2012)