Corporate participation within deep seabed mining raises unique challenges for international law. Commercial investment by private corporate actors in deep seabed mining is increasing. The deep seabed beyond national jurisdiction (the Area) comprises almost three-quarters of the entire surface area of the oceans, and it is home to an array of prized commodities including valuable metals and rare earth elements. These resources constitute the common heritage of mankind. Acting under the United Nations Convention on the Law of the Sea (UNCLOS), the International Seabed Authority (ISA) is responsible for regulating the Area for the benefit of humanity and granting mining contracts. Although mining activities in the Area remain at the exploration stage, in recent years, there has been a marked growth in investment by private corporate actors, and an increasing impetus towards exploitation. This increasing corporate activity presents challenges, including in relation to matters of common management, benefit sharing, marine environmental protection and investment protection. In part, these challenges stem from the often-contentious role of non-state actors, such as corporations, within the international legal system. A product of its history, the UNCLOS deep seabed regime is an unlikely hybrid of capitalist and communist values, embracing the role of private actors while enshrining principles of resource distribution. As technological advances begin to outstrip legal developments, this study advances the discourse by addressing the extent of any tension between corporate commercial activity in the Area and the achievement of the common heritage of mankind.