HONG KONG (AP) — Global investor access to China's financial markets is widening further with the launch of a bond trading link with Hong Kong.

Officials banged a gong and clinked glasses of champagne on Monday morning as they officially kicked off trading on the long awaited Bond Connect link.

It's the latest channel to link up financial markets in Hong Kong, a global financial center, and mainland China, where authorities are gradually lowering restrictions for overseas investors.

Initially, investors can get "northbound" access via Hong Kong financial institutions to mainland China's interbank bond market, the world's third largest at $9.4 trillion in value.

Officials say they're still exploring "southbound" access for mainland investors.

In 2014, Hong Kong launched a stock trading link launched with Shanghai, followed by one last year with Shenzhen.