I think it means that the cost for borrowing for 10 year US treasury is higher than the cost of borrowing for 10 year Chinese government bond. It means the market believes that the Chinese Government Bond has a lower risk of default compared to US treasury.
Hardly has anything to do with default. It’s almost exclusively related to the economic prospects rather than defaulting.
It just means investors have higher confidence that they will get their principal and interest back and hence are more willing to take a lower interest rate on their investment compared to US treasury.
The yield spread can mean many things with a broad set of causes. Technically, neither China’s government bonds or US treasuries can “default” in the classic sense because both country can “print”.
The current UST yields reflects US investors expectations of future FED rate hikes in order to fix the 4 decades high inflation in the US right now. The yield also has to do with an investors expected returns to account for inflation itself(i.e. if inflation is 5%, I need an interest rate of at least 6% assuming everything else is equal).
The central bank sanctions on Russia’s FX reserve have also impacted us dollar assets in central banks across the world. As Russia uses yuan more, demand for Chinese bonds will increase, lowering their Chinese bond yields, as well as from other central banks who also diversifying and adding more yuan holdings to their reserves. While the opposite is true for USD as people slowly sell US treasuries, lowering price and raising rates.
And also, let’s not forget that with China’s current covid lockdowns and outbreak, China’s central bank is likely going to keep yields low in order to support the economy, so it’s not all good news for China either.
Anyhow, sovereign bond yields have multiple causes that could explain the spread among different countries (it’s already complex enough looking at the rate curve convexity among different maturities within the same nation) and most of the time the underlying conditions have completely opposite ramification than what appears at the surface.