多家券商的策略师对此表达担忧。SMBC日兴证券的丸山伦人指出，该投资计划「极有可能对长期及超长期利率形成上行压力」，因为财政支出会先行，而经济成长效益则要到后期才能显现，这意味著日本的债务对GDP比率可能暂时上升。大和证券的首席策略师大谷骏也在报告中表示，该计划「将对政府债券市场产生一定的负面影响」，且投资能否带来预期成长的不确定性可能导致风险溢价上升。
市场已经出现对日本债券需求减弱的迹象。周四的20年期国债拍卖需求为2025年5月以来最弱，投标倍数跌至3.0以下，远低于12个月平均值。日本保险公司在5月净卖出国内超长期国债，全球基金经理也开始减少对日本长期国债的部位。此外，日本央行可能在升息方面落后于形势，加上高市更广泛的财政议程（包括可能的食品消费税减免），都持续为日本债市前景蒙上阴影。
Bond strategists are warning that Japanese Prime Minister Sanae Takaichi's $2.3 trillion investment plan, which envisions over ¥370 trillion in public and private spending over 14 years, risks putting fresh pressure on Japan's government debt market. The government has not yet specified how much additional fiscal spending will be needed, and analysts at major brokerages caution that greater government borrowing could push long-term bond yields higher.
Strategists from SMBC Nikko Securities and Daiwa Securities have voiced concerns about the plan's impact. Rinto Maruyama of SMBC Nikko noted a high probability that the plan will exert upward pressure on long-term and super-long-term interest rates, as fiscal outlays would precede any growth dividends, potentially raising Japan's debt-to-GDP ratio in the interim. Daiwa's chief strategist Shun Otani warned the plan would negatively affect the bond market, with uncertainty over whether investments will deliver expected growth likely resulting in higher risk premiums.
Signs of weakening demand for Japanese government bonds are already emerging. A 20-year bond auction on Thursday drew the weakest demand since May 2025, with the bid-to-cover ratio falling below 3.0, well under the 12-month average. Japanese insurers sold domestic super-long bonds in May, reversing earlier purchases, while global fund managers have also begun reducing exposure to long-dated Japanese government debt. Meanwhile, concerns that the Bank of Japan may be behind the curve on rate hikes and Takaichi's broader fiscal agenda, including a possible food sales tax cut, continue to cloud the outlook for Japan's debt market.