Healthcare Ownership Transparency Act This bill requires health care corporations that participate in Medicare to disclose private equity interests and related financial information. Specifically, the bill requires corporations, as part of the Medicare enrollment and revalidation processes for providers and suppliers, to disclose information about debts, assets, financial transactions, and other information. Providers that are controlled by private equity funds (e.g., venture capital funds) must disclose similar information as well as specific information relating to the private equity fund, such as the percentage of equity contributed by the partners of the fund. The Government Accountability Office must use this information to periodically evaluate the extent to which health care consolidation is taking place and the effects of private equity in health care on costs, staffing, and other factors. The Department of Health and Human Services (HHS) must also establish a task force to address and limit the role of private equity and consolidation in health care. HHS may prohibit certain mergers or acquisitions until the task force has had sufficient time to assess whether there are abusive practices in specific health care sectors or by health care entities.