(BLOOMBERG) - To a world full of fixed-income investors starved of safe assets with attractive yields, China's government bonds had become a tempting sight in recent years. However, red flags are now being hoisted. A series of government crackdowns on everything, from property developers to technology firms, is triggering questions about whether a sudden change in regulations could harm foreign investment in the securities. While positive inflation-adjusted interest rates and relatively tame volatility are keeping some fund managers bullish on China's sovereign debt, the regulatory risk is combining with a lacklustre credit rating to dampen the allure. That is making Chinese bonds a less likely candidate to challenge US Treasuries as global haven assets, impeding Beijing's push to promote the renminbi's worldwide usage and dent the dollar's dominance. "I can't help but feel a higher regulatory risk for the nation's bonds," said Mr Akira Takei, a global fixed-income money manager at Asset Management One in Tokyo who has yet to buy the securities. "Although I don't expect any restrictions to be introduced in China's government bond market, I have to examine how tighter regulations ou...