The US Treasury has just sold $25 billion of 30-year bonds at a yield of 5.216%. That's the highest rate the government ha s paid on 30-year debt since 2001. That effectively means the interest rates which the US taxpayer pays the bond holders has soared massively in the last few years.The reason everyone should care is because government bond yields determine the value of equities, corporate debts, and even mortgages. Let's be clear, America can still sell its debt. The vital question is who's buying it an ...