'''Decoupling modification''' is a [[tax]] terminology resulting from the [[federal tax law]] enacted March 9, 2002, which created a new tax deduction for "bonus depreciation" that threatensthreatened to cost states very large amounts of revenue.{{citationneeded|date=January<nowiki><ref>http://www.ovguide.com/decoupling-modification-9202a8c04000641f8000000013a2d17b</ref></nowiki> 2012}}Federal Bonus Depreciation, Section 168(k) of the Internal Revenue Code, <nowiki><ref>http://web.utk.edu/~jwachowi/hr3090.html</ref></nowiki>allows the acceleration of depreciation on federal tax returns, i.e., writing off a higher amount of depreciation for the first year an asset goes into service. <nowiki><ref>https://revenue-pa.custhelp.com/app/answers/detail/a_id/419/~/what-does-it-mean-to-decouple-from-federal-bonus-depreciation%3F</ref></nowiki> States that refuse to accept this method of calculating depreciation for state taxes, for example, Iowa and Maryland, publish forms with instructions so stating.<nowiki><ref> http://iowa.gov/tax/taxlaw/11SF512D.pdf</ref><ref></nowiki>http://forms.marylandtaxes.com/current_forms/500dm.pdf</ref>
