Find out the state in which the business is registered. In many cases, the business is registered in the state where its business offices are located. You can find this information from any corporate letterhead or from a company's website. Sometimes, an LLC is not registered in the state where its offices are located, but in a corporate-friendly state, such as Nevada or Delaware.
Contact that state's division of corporations. Most states maintain LLC registration information online. In this instance, simply go to the department's website and do a search for the business entity. If the business is in the database, it will most often show you the registered address, as well as the names and addresses of the LLC's members. If the Division of Corporations does not maintain a website, you can call the office and request the filing information for a business entity.
Contact the registered agent. Most of the time, the LLC members will be listed on the filing information provided to the state. However, some states do not require disclosure of member information and the only contact information listed will be that of the registered agent. In this instance, you can contact the registered agent and request member contacts.
Get expert help. If you are looking for LLC member information to pursue legal action, it may be best to contact a lawyer first or the state's secretary of state.