The large amount of interest from foreign investors demonstrates that company finances are secure, Chiang said.
THSRC planned to issue overseas convertible bonds worth US$200 million, but decided last month to raise US$300 million instead as many overseas investors had shown interest in subscribing to the bonds, Chiang said.
The five-year bond issuance is being managed by Deutsche Bank's Hong Kong branch and is expected to be complete by January, he said.
Besides subscribing for bonds, some foreign investors are also buying THSRC shares on the market, Chiang said, without identifying investors.
The presence of foreign shareholders means THSRC's finances would be more stable as it would mean greater corporate governance, he added.
Media reports had it that investment bank Lehman Brothers was mulling to invest in THSRC, but Chiang declined to comment on it.