De minimis non curat lex

De minimis is a Latin expression meaning about minimal things, normally in the locutions de minimis non curat praetor ("The praetor does not concern himself with trifles") or de minimis non curat lex ("The law does not concern itself with trifles") a legal doctrine by which a court refuses to consider trifling matters.Queen Christina of Sweden (r. 1633–1654) favoured the similar Latin adage, aquila non (the eagle does not catch flies).

The general term has come to have a variety of specialised meanings in various contexts as shown below, which indicate that beneath a certain low level a quantity is regarded as trivial, and treated commensurately.

Under U.S. tax rules, the de minimis rule governs the treatment of small amounts of market discount. Under the rule, if a bond is purchased with a small amount of market discount (an amount less than 0.25% of the face value of a bond times the number of complete years between the bond's acquisition date and its maturity date) the market discount is considered to be zero. If the market discount is less than the de minimis amount, the discount on the bond is generally treated as a capital gain upon disposition or redemption rather than as ordinary income. Under Internal Revenue Service guidelines, the de minimis rule can also apply to any benefit, property, or service provided to an employee that has so little value that reporting for it would be unreasonable or administratively impracticable; for example, use of a company photocopier to copy personal documents – see de minimis fringe benefit. Cash is not excludable, regardless of the amount.

Specifically in U.S. State income tax, de minimis refers to the point at which withholdings should be initiated for a nonresident working in a state which taxes personal income. Not all U.S. states levy income taxes, and there's little consistency among nonresident de minimis standards for those that do. Some states base de minimis on the number of days worked (although the definition of what counts as a workday has been controversial), others on the dollars earned or a percentage of total income derived from work in the state, still others using a combination of methods. These inconsistencies have led to repeated attempts to pass the so-called Mobile Workforce State Income Tax Simplification Act without success.

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