Assuming Institution
When banks and other financial institutions go under, regulators often take steps to ensure that the assets of the failed company get taken up by other healthy organizations (See: Assisted Merger). The healthy companies that receive these assets are called the assuming institution.
Often times, the government will facilitate the transfer of assets to the assuming institution by providing some guarantees. Obviously, coming from a failed company can damage the appeal of assets, so this government backing can help smooth out the transfer. The overall goal is to keep the financial system humming, despite the failure of a particular organization.