Treasuries plunged, with 30-year bond yields climbing the most since at least 1977, amid concern that a Donald Trump administration and a Republican-led U.S. Congress will unleash a wave of spending to boost the U.S. economy, triggering a surge in inflation.

Adjusted for current yield levels, which are close to historical lows, the magnitude of the day's rise hasn't been exceeded in data compiled by Bloomberg going back to February 1977. Benchmark U.S. 10-year yields rose above 2 percent for the first time since January as a bond-market measure of inflation expectations climbed to the highest since July 2015. A gauge of the yield curve steepened as longer-dated debt underperformed.

The plunge marked a turnaround from earlier in the day when U.S. debt led a global rally in government bonds during Asian trading hours as it became clear Trump had pulled off an electoral upset. The initial safe-haven bid gave way to expectations that Trump, who pledged during his campaign to cut taxes and outlay as much as $500 billion on infrastructure, would embrace policies that could widen the budget deficit and accelerate the pace of price gains.