Bond repricing: the cost of refinancing in 2026

Borrowers can face a higher price of money before their revenues change. An outstanding bond keeps its fixed coupon, but its next refinancing will be negotiated at prevailing rates. A project can retain the same commercial prospects and become less attractive when the rate used to value its future cash flows rises. The repricing begins in markets; its consequences work through contractual payment dates. 2

The U.S. Treasury’s official curve provides a concrete reference. Between September 1 and September 29, 2026, the nominal ten-year yield rose from 4.79% to 5.26%, an increase of 47 basis points. The thirty-year yield moved from 5.27% to 5.59%, up 32 basis points. These observations belong to the Treasury’s constant-maturity par yield curve. Par means a price equal to face value. These series do not track the coupon or price of one particular bond throughout the month. 1

A basis point is 0.01 percentage point. The ten-year change is therefore 5.26 − 4.79 = 0.47 percentage point, or 47 basis points. It shows that long-term U.S. financing became more expensive over this period. It does not establish a permanent floor above 5% or identify a single cause for the move. 1

Source: U.S. Treasury. Constant-maturity nominal par yields, not the price history of an individual bond. Common zero-based scale, 0 to 6%. Calculated increases: (5.26 − 4.79) × 100 = 47 basis points and (5.59 − 5.27) × 100 = 32.

Analysis as of September 29, 2026. U.S. observations run through September 29; the latest observation in the ECB series retrieved was September 28. IMF projections retain the date and assumptions of the April edition.

A long yield contains several expectations

Bond repricing means a reassessment of bond prices and yields. For a security with fixed cash flows, a higher required yield implies a lower price: the same future payments must offer the new buyer a higher return. This follows the cash-flow discounting principle described by the ECB. 2

A common decomposition separates a long yield into the average expected short-term rate over the bond’s horizon and a term premium. In the chosen model, the premium is the difference between the yield and that expected average path. It incorporates compensation for interest-rate risk and can be negative. The Federal Reserve’s Kim–Wright documentation emphasises that these components are estimates subject to uncertainty and revision. 5

This distinction matters when interpreting monetary policy. The policy rate concerns the very short term; a ten-year bond spans many future decisions. A central bank can raise its rate today while long yields fall if its message sufficiently lowers expected future rates or the term premium. More persistent inflation expectations can instead keep long yields elevated. Our analysis of Fed decisions and the term premium examines this mechanism in its September 14 setting. 5

Debt supply and investor purchases affect the terms on which the market absorbs securities, including through the term premium. Adding supply as a third, independent component on top of expected rates and that premium risks double counting. Nor does the decomposition directly measure how much each driver contributed to this month’s increase. 5

European and Japanese benchmarks mean different things

For September 28, the ECB estimated a nominal ten-year spot rate of 3.63%, rounded to two decimals, using its sample of AAA-rated euro-area government bonds. The series uses the Svensson model and continuous compounding. It represents the yield on a hypothetical zero-coupon security; it is neither an average across all European sovereigns nor the coupon on a particular issue. 2 3

In Japan, the September 18 decision, effective from September 24, targets an overnight call rate of around 1.25%. Japan’s policy rate has a different maturity and currency from a long-term U.S. yield. Subtracting one from the other to rank countries would lose those distinctions. 4

Central-bank balance sheets also need to be read individually. The Fed’s September 16, 2026 implementation note directs the rollover of all principal payments from its Treasury holdings and the reinvestment of agency-security repayments into Treasury bills. It also permits short-security purchases, when appropriate, to maintain ample reserves. Describing all central banks as having stopped buying debt would misrepresent the U.S. position. Purchases intended to maintain bank reserves and a programme buying long-dated debt have different effects on the duration held by markets. 7

The Fed also raised its target range to 3.75–4.00% on September 16. Short rates, the composition of the central bank’s portfolio and long yields are separate objects that deserve separate attention. 6

The budget bill follows the maturity calendar

A long yield matters to a government when it issues new securities or replaces debt that has matured. An outstanding fixed-coupon bond retains its contractual payments as its market price changes. For floating-rate debt, transmission depends on the reference rate and reset dates. The maturity schedule and composition of the stock determine how quickly new financing conditions enter interest spending.

Consider a hypothetical example: a constant debt stock of 1,000 billion, carrying a fixed 2% coupon, with 20% replaced at the start of each of the following five years by bonds issued at par with a 5% coupon. The new securities do not mature during the exercise. With no additional debt, no amortisation and full-year coupon payments, annual interest rises from 20 billion to 26 billion after the first replacement. After five rounds, it reaches 50 billion. The extra bill is 6 billion in the first year, then 30 billion a year once the whole stock has rolled over.

Source: l0g calculation, hypothetical example described in the text. Billion currency units, full-year coupons. Constant debt stock, start-of-year refinancing, fixed rates, no replacement securities maturing within the five years. Interest bill = 20 + 1,000 × cumulative share refinanced × (0.05 − 0.02). No country forecast.

This calculation describes no actual government. Its formula is debt stock × cumulative share refinanced × coupon difference. In the first year: 1,000 × 20% × (5% − 2%) = 6 billion. Additional borrowing, issuance partway through the year or floating-rate clauses would alter the result. The example isolates the maturity calendar; it is not a fiscal forecast.

Our investigation of governments shortening their refinancing horizon examines this distinction. It also helps explain why Russia’s budget and banking circuit must be read alongside bond terms rather than by applying one rate to the entire debt stock.

The global scale provides context without replacing this contract-level analysis. In its April 2026 Fiscal Monitor, the IMF estimated that global public debt reached just under 94% of GDP in 2025 and projected 100% in 2029. That projection depends on the edition’s assumptions and future policies. A global ratio alone cannot identify a country’s borrowing currency, maturity profile or available assets. 9

Other assets face the same changing price

Private credit is priced around a reference rate, compensation for the borrower’s risk and contractual terms. A higher reference rate can make funding more expensive, but a narrowing credit spread can offset part of that increase. An existing fixed-rate mortgage and a corporate floating-rate facility therefore experience the change at different times.

For equities or an industrial project, one channel runs through discounting. With cash flows unchanged, a higher discount rate reduces present value. This does not automatically predict a lower share price: expected revenue, margins and risk premiums can also change. In its September 23, 2026 report, the OECD identifies higher long rates as increasing government borrowing costs and weighing on equity valuations. 8

A calculation makes the price of time visible. €100 received in ten years, discounted at a hypothetical constant annual rate of 3%, is worth €74.41 today. At 5%, its present value is €61.39. Both calculations use 100 / (1 + rate)¹⁰. The cash flow stays the same; only the simulation’s rate changes. These hypothetical annually compounded rates are not equated with the market series cited above. 2

Duration measures interest-rate sensitivity. For a fixed-cash-flow bond, modified duration approximates the relative price change caused by a small yield movement. With larger moves, the curvature of the price-yield relationship, known as convexity, matters more. A security’s remaining maturity and its financial sensitivity are not interchangeable. 10

For savers, a higher sovereign yield can make some bonds more attractive relative to other investments. Currency, inflation, tax treatment and the holding period still belong in the assessment. A quoted yield is neither a universal coupon nor a guaranteed realised return when a bond is sold before maturity. 11

Growth will shape the next move

The OECD’s September outlook describes more persistent energy-price and inflation pressures, with higher interest rates moderating near-term growth. It identifies a further increase in long sovereign yields as a downside risk. This supports close attention to financing conditions; it does not establish a rule that yields must remain at their current levels. 8

Clearer disinflation or weaker growth can change expectations of future short rates. A flight to safety can alter the term premium. Financing needs or persistent inflation can instead sustain pressure. The size of these effects will depend on incoming data and investor behaviour; September’s increase cannot quantify them in advance. 5 8

The cost of capital becomes visible in contracts and payment dates. Following its transmission requires connecting observed yields with exposed coupons, refinancing schedules and expected future cash flows. At that level, bond repricing starts to change a budget, a project or a valuation.

Sources and documents

Method and limitations

U.S. yields are nominal, in percent per annum, at constant maturities on the Treasury’s par curve. The ECB observation is a modelled nominal spot rate with continuous compounding for the AAA sample; the Japanese rate concerns overnight money. These benchmarks do not form a homogeneous country ranking. The ECB’s published 3.6313186552% is rounded to 3.63%. Changes in U.S. yields are calculated in basis points.

The interest and present-value calculations are hypothetical examples with constant assumptions. They describe neither an actual government’s payments nor an observed asset price. Term premiums are model estimates; no numerical allocation of September’s increase across its drivers is presented. OECD and IMF outlooks remain attributed to those institutions and their publication dates.