Most debt investors shrugged off solid industrial output data for December and instead clung to views that the economic recovery pace would slow down, persuading the central bank to keep rates extremely low for several more months.
"We have confusing cues from overseas," said Park Yu-na, a fixed-income analyst at Hyundai Securities. "There are fears of possible tightening in the United States and China while the global economy faces more uncertainty. This should make the Bank of Korea's rate decision much more difficult."
A smaller issuance plan for February also boosted debt-buying interest. The government said late Thursday that it would issue 6.41 trillion won ($5.55 billion) in treasury bonds for February after selling 9.46 trillion won in January.
The bond yield curve flattened as the benchmark 5-year treasury bond yield fell 5 basis points to 4.82 percent while the one-year bond yield slid 3 basis points to 3.22 percent. The March contract on 3-year treasury bond futures soared as much as 30 ticks before unwinding some gains to end 21 ticks higher at 109.70.