Fifty-three basis points from two to thirty

The headline about the Treasury market is that yields are at levels not seen since 2007. That is true, and it is the least informative thing the data says. The long end has been near those levels since the start of the month. What has changed in September is the front, and it has changed a great deal.

On 21 September the two-year Treasury yielded 4.76 per cent and the thirty-year 5.29 per cent, according to the Federal Reserve's H.15 release. The gap between them was 53 basis points, the narrowest reading of 2026. On 2 January the same spread was 139 basis points. On 1 September it was 88. The curve has flattened by 35 basis points in three weeks without the long end doing any of the work.

The arithmetic is worth setting out plainly. Between 1 September and 22 September the two-year rose from 4.39 per cent to 4.71 per cent, a move of 32 basis points. The ten-year rose from 4.79 to 4.96, seventeen basis points. The thirty-year went from 5.27 to 5.29, two basis points, on the Treasury's daily par yield curve. Almost the whole repricing sits inside five years.

That distribution tells you what the market is repricing. A sell-off concentrated at the front is a sell-off about the Federal Reserve. A sell-off concentrated at the back is a sell-off about the price of duration — supply, inflation risk, the compensation investors demand for holding a thirty-year claim on the government. September has produced the first and not the second. The Federal Open Market Committee raised the target range to 3.75 to 4 per cent on 16 September and published projections showing no cuts in 2027. The two-year has been working through what that implies ever since, helped on Tuesday by hawkish remarks from Fed officials.

On any conventional reading, that is the constructive version of high yields. It says the long bond is not being sold because investors have lost confidence in the fiscal path; it is being held roughly where it was while the policy rate is repriced underneath it. The compensation demanded for lending for thirty years rather than two has fallen by more than a third since January. Term premium is not what is rising.

Two features complicate the reading. The first is where the curve peaks. The twenty-year yielded 5.33 per cent on 22 September against the thirty-year's 5.29, so the highest yield on the curve is not at its far end. That inversion has been persistent, at two to four basis points for most of September, and it was zero on 1 September. It is a structural artefact as much as a signal — the twenty-year is a less liquid point that the buyers of long duration tend to skip — but it does mean that an investor being paid the most for taking duration is not the one taking the most of it.

The second is the level itself. The thirty-year at 5.29 per cent is the highest since June 2007. The twenty-year at 5.33 per cent, and 5.40 per cent on 15 September, is the highest since July 2007. The ten-year touched 5.01 per cent on three days this month, which it had not done since July 2007 either. A flat curve at these levels is a different object from a flat curve at two per cent, because it sets the cost of thirty-year money for every borrower that prices off it. The 30-year auction on 17 September cleared at 5.308 per cent, the highest at that sale since 2001, and it cleared well.

The front end is also at a level that means something. At 4.76 per cent, the two-year is where it last stood on 1 July 2024, back when the policy rate was more than a point higher than it is now. The effective federal funds rate was 3.88 per cent on 21 September. A two-year note yielding 88 basis points above the overnight rate is a security priced for further tightening, not for a pause.

Which leaves the question the curve is now posing. If the front keeps rising and the back does not, the two meet. A flat or inverted curve at five per cent is the configuration that precedes a growth scare, and it arrives without any of the usual warning from the long end, because the long end has already been at these levels for weeks and has stopped reacting. On Tuesday the two-year gave back five basis points and the thirty-year did not move, which widened the spread to 58. That is the sort of day that decides whether 53 was a floor or a waypoint.