T30I

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

Dirty price move

-£0.446

07 Aug 2026 → 09 Sep 2026

Start dirty price

£99.300

model £99.300

End dirty price

£98.854

model £98.854

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	+£0.354	The passage of time at an unchanged yield: the bond simply gets one period closer to redemption.
Rolldown	+£0.033	The yield change that comes from the shorter remaining maturity — rolling down the same curve.
Variation	-£0.845	The move in the curve itself between the two dates.
Unexplained	+£0.012	The residual between the traded prices and what carry, rolldown and variation account for.

The curve, then and now

Market data as of 07 Aug 2026 and 09 Sep 2026.

T30I

What moved the price

The curve, then and now

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