U.S. bonds staged a late-day rally Monday, rounding out the best month for bonds since May 1995, as stocks plunged anew.

The 30-year Treasury bond's price rose $10.64 per $1,000 face value, pushing its yield down to a record low 5.27% from 5.33% on Friday. But shorter-term yields were mostly unchanged.

Meanwhile, the rush into bonds continued in Tokyo today, where the yield on Japan's 10-year government bond fell to 0.995%--its lowest ever, and perhaps the lowest in the history of bond markets.