"about 95 percent of Japanese government bonds are owned by Japanese investors. Of that figure, 60 percent is held by Japan Post Bank and other financial institutions."
Source: Japan's bond market has become ticking bomb
BY YOICHI FUNABASHI
ASAHI SHIMBUN
EDITOR IN CHIEF
2010/08/11
http://www.asahi.com/english/TKY201008100353.html