TLT closed September 15 2026 at 80.71 against 81.73 at the September 9 close and 81.00 on the morning of September 10 - a further 1.2% decline in the long-duration Treasury ETF across the window, to a new low for the cycle. IEF closed 90.82. Massive's daily aggregates lag one session, so September 16 is not yet in the feed; the Massive treasury yield endpoint returned an empty result set for September 15 on the current plan.