The US 30-year yield climbed as much as four basis points to 4.999% on Wednesday before stabilizing, mirroring similar moves in the UK and Japan, where a deepening selloff pushed borrowing costs to the highest this century.  

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"The signal is quite clear that there is still at these levels no appetite for the long end," Ella Hoxha, head of fixed income at Newton Investment Management, told Bloomberg TV this week. "The risks are there's going to be less appetite going forward."

In the US, the moves underscore the pressure on the government from investors who want more compensation as they're called on to finance spending plans and tax cuts by the Trump administration.

At the same time, interest-rate strategists say US President Donald Trump's efforts to gain control of the Federal Reserve in pursuit of interest-rate cuts is helping push up long-term yields relative to short maturities, which are more closely tied to the rate set by the Fed. Rate cuts might keep upward pressure on inflation rates that still exceed the central bank's 2% target, strategists say.

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Fed Governor Christopher Waller, who dissented from the central bank's July decision to keep rates steady in favor of cutting them and has been among Trump's candidates to succeed Jerome Powell as chair of the central bank, reiterated Wednesday on CNBC he favors cutting rates at the next meeting on Sept. 16-17.

Contracts for predicting Fed moves have priced in about 90% of a quarter-point rate cut this month, and fully price in two cuts by year end. 

In July, the majority of Fed policymakers viewed the policy rate setting of 4.25%-4.5% as appropriate based on employment and inflation trends. St. Louis Fed President Alberto Musalem reiterated that view Wednesday. 

Expectations for Fed rate cuts rocketed higher in early August after US government-compiled employment data showed a slump in job creation over the previous three months. Jobs data for August are slated to be released Friday, and a gauge of July job openings to be released Wednesday at 10 a.m. New York time is expected to show a decline consistent with a weakening labor market.

Data that reinforces expectations for Fed rate cuts could backstop the Treasury market, where JPMorgan's weekly Treasury client survey and CME Group's Treasury futures open-interest data indicated that traders cut long positions and added to shorts over the past week.

"A downside surprise in openings, especially if coupled with higher layoffs and lower quits, could be a good combo to see dip-buying in Treasuries," said Evelyne Gomez-Liechti, a strategist at Mizuho International Plc. 

Yields on Treasuries maturing in two to five years reached the lowest levels since early May last week, producing some of the widest differentials between short- and long-term yields in years.

The divergence is "an unusual situation reflecting investors' wish for more compensation to hold long-term bonds," BlackRock Investment Institute strategists including Wei Li wrote in a note.