Add API to Manage Parent-Child Company Relationships
Currently, there is no public API to manage a parent-child company relationships. This prevents integrators and other API consumers from utilizing this functionality. Adding a public API to manage these relationships would enable integrators and other API consumers to take full advantage of this feature and get more value out of the HubSpot CRM.
Related Developer Forum topic: https://integrate.hubspot.com/t/parent-child-relationships-for-companies-in-the-api/3466/