You don't need to cite all your sources in APA format. However, providing the source of data and information you use in your presentation can add to the credibility and impact of your analysis and recommendations. You can note sources briefly on your slides or mention them during your presentation.
Don't let your audience wonder 'where did they get those numbers' or 'how do they know that'?
APA Style (American Psychological Association) is generally used in business
APA style guides are at http://library.queensu.ca/help-services/citing-sources
Also, guides for business, government and legal sources.
