Three minutes is not a long time, but when you're asked to give a three minute speech in front of a large group, it seems long enough. The nature of the group you're addressing will be the primary factor in determining your topic, but there will always be a range of suitable subjects within that topic.
Select a topic providing interesting information of general or specific interest to the group. Consider your personal experiences, people you have met or information you have learned. If you have just returned from an African safari, share your adventure with the group as long as it is relevant to the subject at hand. Perhaps an upcoming project could be likened to a safari into an unknown environment. Other informational topics include discussions on events, local authors, organizations, government agencies and personalities.
Educate the group on a subject matter within your field of experience. Give them a nugget of valuable information which will help them at work or in some other part of their lives. Consider your expertise when selecting a topic. If you have mastered a popular computer program, give the group some practical tips. A speaker in human resources can give a brief speech on dressing for success, or ways to approach an interview. A real estate professional might give a brief talk on staging a home for sale, while someone in the medical field could talk about how HIPPA laws affect his business.
Use the three-minute speech to campaign for a change in company policy or a cause you think the business should support. This small chunk of time is ideal for introducing your idea to the group. You aren't meant to be the focus of the topic, but rather the means to communicate an idea. For example, if you want your business to start supporting a local charity, use this time to speak about the good work they do and how it benefits the local small business community. A campaign speech may not support a particular cause or person but can still encourage the group to get out and get involved.
Inspire the group with a motivational speech. Aim to uplift the group, to give it a more positive perspective on life and business. You don’t need to be an experienced motivational speaker to select this type of topic. Recount an inspirational story you have heard or experienced, perhaps one where a small business owner overcame long odds to save his company or do great things for his employees.