T30I

4 1/8% Index-linked Treasury Stock 2030 · GB0008932666

Return

+£0.259

04 Sep 2026 → 02 Oct 2026

Start dirty price

£344.189

model £303.449

End dirty price

£344.449

model £302.311

Mark-to-market is the traded price; mark-to-model discounts the remaining flows along the fitted curve. The decomposition below is computed on the model prices.

What moved the price

Effect	Contribution	What it is
Carry	+£1.800	The passage of time at an unchanged yield: coupons earned plus the bond getting closer to redemption.
Rolldown	+£0.105	The yield change that comes from the shorter remaining maturity — rolling down the same curve.
Variation	-£3.042	The move in the curve itself between the two dates.
Unexplained	+£1.397	The residual between the traded prices and what carry, rolldown and variation account for.

The curve, then and now

Market data as of 04 Sep 2026 and 02 Oct 2026.

T30I

What moved the price

The curve, then and now

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