Waterfall Forensics.

Tie-out heatmap

Wells Fargo Mortgage Backed Securities 2006-AR1 Trust

Every comparison the backtest ever made, on one screen: one column per distribution date, one row per class, colored by the worst absolute delta across interest, principal, and ending balance. The near-uniform field is the point. The few cells that broke a dollar are listed below, worst first.

10

periods replayed

99.3%

of 420 points within one dollar

3

points off by more than a dollar

I-A-1I-A-RII-A-1II-A-2II-A-3II-A-4II-A-5II-A-6B-1B-2B-3B-4B-5B-6
2006
exact to the centwithin a pennywithin a dollarover a dollarno comparisonhover any cell for its worst delta

The exception queue

3 of 420 comparisons sit more than a dollar from the trustee's figure. This is the entire list. Of the rest, 222 matched to the exact cent and 161 differed by cents, rounding-sized and never compounding.

DateClassFigureComputedReportedΔ
2006-12-26II-A-2interest1,372,419.391,372,420.681.29
2006-05-25II-A-2interest1,444,350.961,444,349.861.10
2006-06-26II-A-2interest1,429,851.901,429,850.831.07

state rolls forward on computed values only — reported figures are never fed back in, so an engine error would compound rather than hide