Citing your references...

Always important to acknowledge where you obtained a piece of financial data if you are quoting it within an assignment....

Tesco plc recorded gross profits of £4,607 million in 2010 ( Keynote Company Report, 2010 )

And in your bibliography...

Keynote Report ( 2011 ) Company Information : Tesco [online] Accessed via library.beds.ac.uk on January 17th 2011