The increase in open innovation and the need for collaboration in the business and scientific environments have led to a growing need to deal with co-ownership. Some legal systems have clear co-ownership rules that are specific to IP rights. However, in Mexico intellectual property is dealt with under the general rules applicable to all types of property, meaning that at times the provisions are not as clear as they could be, considering that the majority of the laws are designed to deal with tangible property rather than intangible assets such as IP rights. Therefore, the laws must be interpreted in terms of the unique features of IP rights. This chapter examines such interpretation in the context of IP-based business transactions.