Ten-year Treasury yields fell three basis points, or 0.03 percentage point, last week to 1.72 percent, and are down from 1.88 percent at the end of 2011, according to Bloomberg Bond Trader prices. The yield fell three basis points to 1.68 percent at 9:48 a.m. in London.

Few investors or strategists foresaw the rally. Ten-year yields were expected to be higher this year for at least two- thirds of the Group of Seven nations plus Brazil, Russia, India and China, according to data compiled by Bloomberg.

Rather than a referendum, on government actions, gains in government securities are more of a reflection of central banks supporting government debt, according to Jamie Stuttard, the London-based head of international bonds at Fidelity Investments, which oversees $1.58 trillion.

Benchmark Rates

Benchmark interest rates are close to zero in the U.S. and Japan and are a record low 0.75 percent in Europe.

After buying $2.3 trillion of Treasuries and mortgage- related bonds, the Fed said Oct. 24 it would continue its unprecedented stimulus measures by purchasing $40 billion of home-loan securities a month until the labor market improves "substantially."

While payrolls expanded by 171,000 in October following a 148,000 gain in September, a U.S. Labor Department showed Nov. 2 that the unemployment rate rose to 7.9 percent from 7.8 percent.

The Bank of Japan increased its asset-purchase fund on Oct. 30 by 11 trillion yen ($137 billion) to 66 trillion yen. European Central Bank President Mario Draghi said Oct. 4 the bank is ready to start buying government bonds to help the debt- ridden nations in the region, including Spain.

Spain, Italy

"The only reason these bonds rallied is because of external factors such as liquidity from central banks and a proactive response that Draghi has taken," Fidelity's Stuttard said by telephone Oct. 30. "Without that, there would have been a Spanish government bond crisis in the third quarter."

Spanish 10-year bond yielded 5.74 percent today, down from a euro-era record 7.75 percent on July 27. Ten-year Italian yields dropped to 4.99 percent from 6.71 percent on July 25.