Why 27.5 Years for Residential Depreciation?

[Shafi Noss]

Does anyone know where the 27.5 and 39 year numbers for deprecation schedules came from? They seem so specific, 39 instead of 40, 27.5 instead of 30, does anyone tax savvy know how these numbers got placed?

[Lance Lvovsky]

@Shafi Noss

There is no magic formula as to how Congress derived these numbers decades ago when this was implemented into tax law. Could have been at the advice of industry groups, could be influenced by revenue constraints and revenue raising as required by congressional bills, etc.