Why Borrowing Costs Are Up While the Dollar Is Down

The dollar fell 0.1%, its sixth drop in eight trading days. At the same time, the rate the government pays to borrow for 10 years stayed just under 5%. That rate works like a base price for mortgages and other long loans. WSJ

On September 11, 2026, that 10-year rate was about 4.94%. It was near 5% before new inflation numbers, the report on how fast everyday prices rise. Bloomberg

The order here matters for your money. Borrowing costs moved first. The dollar moved later.

Early September showed the climb. After a solid U.S. jobs report, the 10-year rate rose nearly 2 basis points, or 0.02 point, to about 4.78%, after touching 4.812%. Reuters On September 2, it had slipped 0.2 basis point to 4.794% and was set to end its longest run of daily gains. Reuters The pause was short. Rates rose again into the inflation report.

Late August set the stage. Bond rates rose with the dollar as traders bet more on a rate hike after a speech by Federal Reserve Chair Kevin Warsh. Reuters On August 19, the dollar index fell 0.84% to 98.80. At the same time, the Treasury doubled buybacks of long-term bonds to at least $4 billion each time. Reuters

Earlier months frame the range. The WSJ Dollar Index fell 0.30% to 96.86 in July and 0.11% to 97.49 in June. In May, bond rates were at their highest in a year while oil prices were high.

The broader context here is odd. Higher headline rates did not bring lasting dollar strength. That split points to other pulls from rates after inflation, extra pay for holding long bonds, and how investors were placed.

In my view, the buyback move matters. Doubling long-term buybacks to at least $4 billion each time means less new debt for markets to absorb, like buying back its own IOUs to keep trading smooth. It does not cap rates. It can ease trading and change the discount needed to sell bonds around data and auctions.

Looking at what this means for loans and savings, a move from 4.78% to 4.94% lifts mortgage benchmarks and business borrowing costs together. Six drops in eight days with higher rates warns against seeing a soft dollar as easier policy. It looks more like nervous trading before big news.

The test ahead is inflation pass-through. If inflation keeps higher-for-longer rate bets alive after the Warsh remarks, long bonds will need more extra pay and the dollar will depend on whether U.S. rates after inflation pull ahead of G10 peers. If not, the early-September rise could fade as fast as the late-August move did.