A joint marketing agreement is a legal contract that governs the relationship between two or more companies to collaborate in advertising, promotion and sales. Joint marketing agreements are contracts that allow companies to market for each other and share audiences.Learn how to manage these agreements. New §22.17 creates an exception to opt out requirements for disclosure of nonpublic personal financial information for service providers and joint marketing. Filed with the Securities and Exchange Commission. Yes. Certificates of formation can be filed online through SOSDirect 24 hours a day, 7 days a week. A common misperception is that forming a partnership in Texas requires formal paperwork. However, there actually is no requirement for a written agreement. Businesses form joint marketing agreements to gain market share. One company agrees to promote the other's products to its existing and future customers.