SQA is a form of risk awareness, and is therefore potentially allied to any senior management with a risk management focus.
Within some companies/industries (e.g. insurance), software risks are seen as having mainly financial consequences, and so the main ally might be the financial director.
Within other companies/industries (e.g. retail), software risks are seen as having mainly customer service implications, and so the main allies may be in marketing roles.
In one client, we had useful conversations with the Company Secretariat, because of the due diligence implications of some software risks. These conversations were triggered by Y2K issues, but ranged much more widely.
In practice, SQA often fails to make these alliances, because it gets bogged down in obscure software technicalities and trivialities, which it is incapable of communicating effectively even to software engineers, let alone anybody else.