VBTLX: how its history is extended
VBTLX returns from its first trading day; earlier history from BND, then VBMFX. (represented by the us_bond asset chain before its own history)
Kind
Backfill chain
Extended from
1986-12-12
Through
2026-09-11
Sources
VBTLX → BND → VBMFX
Validation at each junction
| Real series | Stands in before it | Real data from | Overlap (years) | Monthly correlation | Return gap (pp/yr) | Gate |
|---|---|---|---|---|---|---|
| VBTLX | BND | 2001-11-12 | 19.35 | 0.9858 | 0.044 | pass (bars: corr ≥ 0.9, |gap| ≤ 1.0pp) |
| BND | VBMFX | 2007-04-10 | 19.35 | 0.9854 | 0.069 | pass (bars: corr ≥ 0.9, |gap| ≤ 1.0pp) |
Figures on this page are computed from the data store when the page renders; the gate is re-checked every time an extension is used. Method: the lab's tracking standard, lab.data.chains.