Sept 22 (Reuters) - Avis: Moody's Investors Service (Moody's') has assigned definitive ratings of Aa2 (sf) to the AUD 125,000,000 Variable Funding Certificates (VFC's) issued by AB Funding Pty Limited. The transaction is a securitisation of an Australian rental car fleet originated by W.T.H Pty Limited (WTH'), a subsidiary of Avis Management Pty Limited.