President Trump's promise to issue $5,000 "dividend" checks to all American adults if Republicans retain control of Congress has injected fresh uncertainty into the Treasury market just ahead of the upcoming 30-year bond auction, heightening investor concerns about Washington's fiscal discipline and policy unpredictability.

Treasuries fell on Thursday, underperforming European sovereign debt, following the president's pledge made during a campaign event. The benchmark 30-year yield rose 2 basis points to 5.31%. While Trump offered no specifics and the proposal is considered unlikely to become law, the comments arrive with long-dated yields already near their highest levels since the global financial crisis.

The market's focus now shifts to Thursday's $22 billion sale of 30-year bonds maturing in 2056, alongside the release of the U.S. producer price index, with another key inflation reading due later in the week. The move follows Wednesday's decline in Treasuries after Treasury Secretary Scott Bessent proposed buying back up to $6 billion in longer-dated securities, a plan that disappointed investors who had expected a larger repurchase program.

"I'm not saying this alone will trigger a massive selloff in bonds, but it does raise the question of what the Trump administration as a whole is trying to achieve," said Kiyoshi Ishigane, executive chief fund manager at Mitsubishi UFJ Asset Management in Tokyo. "Isn't it contradictory to see Bessent trying to push yields down while such a statement is made?"

Meanwhile, the Treasury market has faced persistent pressure in recent weeks due to renewed Middle East tensions, rising oil prices, and expectations that the Federal Reserve may hike interest rates. Adding to the strain, concerns over the fiscal health of the world's largest economy have intensified as U.S. public debt surpassed $40 trillion for the first time.

Strategists suggest the market's muted reaction reflects a widespread belief that the proposal's probability of realization is nearly zero. "The U.S. economy is already running strong and faces overheating risks, so injecting such a massive fiscal stimulus under existing financing pressures would only amplify the dynamics already present: weaker Treasuries, a softer dollar, and flows into commodities and real assets."

"This policy makes it more binary for investors when assessing Treasuries based on the outcome of the midterm elections," said Eugene Leow, senior rates strategist at DBS Bank. "If Republicans successfully hold both chambers, fiscal issues could worsen sharply."