Yes. If two or more people go into business together without a written partnership agreement, statutory default rules govern the business automatically. While these default rules are typically based on the Uniform Partnership Act (UPA) or Revised Uniform Partnership Act (RUPA), exact default provisions depend on applicable state law and the partnership structure. In general partnerships without an agreement, many state default statutes divide profits, losses, and management authority equally among partners regardless of capital contributions. Furthermore, general partners in an informal or standard general partnership typically face joint or joint-and-several personal liability for business obligations, though specific partner liability depends on the partnership type (such as an LLP or LP) and applicable state law. A tailored written agreement allows co-owners to override state defaults and establish clear equity, buyout, and decision-making terms.