The New York Stock Exchange has proposed a capital tieup with its counterpart in Tokyo, sources said Friday.

In response, the Tokyo Stock Exchange has been studying ways to strengthen ties between the world's two largest bourses, including taking cross-shareholdings of up to 10 percent of each other's stock by 2009, when the TSE is scheduled to go public, the sources said.

The Tokyo exchange is also considering cross-listing of financial products such as stocks and exchange-traded funds, they said.