Reading a spread: one yield minus another

Why it matters

Kitalpha’s 2s10s spread page states, as of 2026-09-15: "The 2s10s spread was 0.33 percentage points on 2026-09-15 — the curve is POSITIVELY SLOPED by 33 basis points, with the longer maturity yielding more than the shorter one.". The figure is small, it carries a sign, and it comes with a word describing the curve’s state. Beside it sits a second computed spread, the 3m10y. A reader used to yields may read a spread as a level, or read its sign as an instruction. It is neither: it is a subtraction, and what a subtraction between two tenors can and cannot say is this lesson’s idea.

The concept

A spread is the difference between two yields on the same date. The 2s10s spread is the 10-year Treasury par yield minus the 2-year; the 3m10y is the 10-year minus the 3-month. Kitalpha computes both each business day from the Treasury’s published par yields, so every value on a spread page traces to two points on that day’s curve. The names give the tenors and the convention gives the order: the longer tenor comes first in the subtraction, so a positive spread means the longer tenor yielded more.

Because it is a difference, a spread is quoted in basis points, hundredths of a percentage point, and it carries a sign. A spread of a third of a percentage point is 33 basis points; a spread below zero says the shorter tenor yielded more than the longer one on that date, which is the shape a later lesson describes as inversion. The state word on the record is the sign in prose, and the record’s statement sentence writes the whole thing out with its date.

Two properties separate a spread from a yield. It is not a level. Two curves sitting at very different heights, one with every yield near two percent and one with every yield near five, can have the same 2s10s spread, because the spread measures the slope between two tenors and not where either of them sits. And it moves for its own reasons: both yields can rise on a day the spread narrows, if the 2-year rises more than the 10-year, so the change in a spread is not the change in the 10-year yield or in the 2-year yield but in the gap between them.

Two spreads on one curve are two different subtractions. The 2s10s and the 3m10y share the 10-year and differ in the short tenor, so their difference on a date is the 3-month yield minus the 2-year yield, the slope of the very front of the curve; they can differ in sign on the same day, and the record’s history shows days when they did. Neither is the curve; each is one slope read from it.

What a spread does not carry is an instruction. Its sign describes the curve’s shape on a date, computed from published yields, and a description of shape says nothing about what anyone ought to do, however often commentary treats the crossing of zero as a message to the reader. The chart below plots the 2s10s over the last year with a rule at zero. Read the line against that rule rather than against its height, and read a move in the line as the gap between two tenors widening or narrowing.

Worked example

Take the 2s10s record as of 2026-09-15. The steps below read today’s spread in percentage points, convert it to basis points, read the previous trading day’s spread, and take the one-day change in basis points. Every figure comes from the spread record, itself computed from the Treasury’s par yields on the two dates.

What to read off the steps. The second line is how the spread is normally quoted, and its sign is the record’s state word in numbers. The fourth line is a change in a gap, not in a yield: it says whether the 10-year pulled further above the 2-year or came closer to it between the two days, and it can carry a different sign from the change in either yield. Nothing in the four lines says why the gap moved, and nothing in them says what follows from it.

Faded example

Now the second computed spread: the 3m10y as of 2026-09-15, the 10-year minus the 3-month. Its value in percentage points is given. Complete the last step: the same spread in basis points.

Retrieval check

Mark your confidence before each answer. Every option carries an explanation; read the ones you rejected too.

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