China is moving away from holding long-term US debt. Their holdings peaked at $1.3 trillion in 2014, and it's down to about $770 billion, give or take a few billion, in the last few months, a decline of 40%. Part of this is selling existing bonds, some of it is redeeming bonds that have matured. They are not buying nearly as much as they used to, and it's not an issue of trust that they won't be paid back. They bought them because they fully expected to be paid back, and they were. The Chinese government is in part worried about capital flight, and is trying to keep foreign currency in the country, partially for trade use and partially to prop up the market for the yuan (which officially trades within a narrow official band but unofficially trades much more widely). They're also shifting to other assets like agency bonds and short-term T-bills and notes, which gets them some profit but keeps dollars cycling back into China. They're not completely out of the T-bond market, but they are reducing their overall position.