Treasury's 30-Year Series Has a Four-Year Hole (2002–2006) That Can Silently Skew Backtests

Treasury stopped publishing the 30-year constant maturity series on February 18, 2002 and didn't resume until February 9, 2006. That four-year gap creates a structural break in yield-curve datasets. Anyone running multi-decade backtests or term-premium regressions should verify their data provider handled the discontinuity explicitly — interpolation can mask the missing point rather than flag it.