* Files with Canada, U.S. regulators
* Sources say company interested in Asian assets
* Shares down 44 pct since January (Writes through with Canadian offering. In U.S. dollars unless noted)
By Cameron French
TORONTO, Aug 30 (Reuters) - Manulife Financial <MFC.TO> filed a mixed shelf offering of up to C$10 billion ($9.4 billion) with Canadian and U.S. regulators on Monday, replacing an existing C$10 billion shelf that was filed last year in Canada only.