"LTD" is short for "Limited", a business form used primarily in the UK. LTD is not a corporate form used in Maryland, and frankly should not be used. The intials INC and LLC are the corporate forms for Incorporations and Limited Liability Corporations respectively. If you are operating a business, you should make sure that you are properly incorporated in the state that you are doing business. If you are properly incorporated, and follow proper corporate formalities, you are shielded from most personal liability. Incorporating is the cheapest liability and financial insurance policy that you can buy and should always be done if you are operating a business.