Act as a Chief Information Security Officer (CISO) for a global financial institution. Develop a multi-year migration strategy to transition the organization's cryptographic infrastructure from current standards (RSA, ECC) to post-quantum cryptography (PQC) algorithms. Your strategy must include an inventory of vulnerable assets, a timeline for hybrid implementation phases, a risk assessment regarding 'harvest now, decrypt later' attacks, and a rollback plan in case selected NIST-standardized algorithms prove vulnerable in the future.