(a) Section 120 excludes from the gross income of an individual employed as a police official by a State, Territory, or possession of the United States, by any of their political subdivisions, or by the District of Columbia, any amount received as a statutory subsistence allowance to the extent that such allowance does not exceed $5 per day. For purposes of this section, the term “statutory subsistence allowance” means an amount which is designated as a subsistence allowance under the laws of a State, a Territory, or a possession of the United States, any political subdivision of any of the foregoing, or the District of Columbia and which is paid to an individual who is employed as a police official of such governmental unit. A subsistence allowance paid to a police official by any of the foregoing governmental units which is not so provided by statute may not be excluded from gross income under the provisions of section 120. The term “police official” includes an employee of any of the foregoing governmental units who has police duties, such as a sheriff, a detective, a policeman, or a State police trooper, however designated.

(b) The exclusion provided by section 120 is to be computed on a daily basis, that is, for each day for which the statutory allowance is paid. If the statute providing the allowance does not specify the daily amount of such allowance, the allowance shall be converted to a daily basis for the purpose of applying the limitation provided herein. For example, if a State statute provides for a weekly subsistence allowance, the daily amount is to be determined by dividing the weekly amount by the number of days for which the allowance is paid. Thus, if a State trooper receives a weekly statutory subsistence allowance of $40 would be $8, that is, $40 divided by 5 for 5 days of the week, the daily amount would be $8, that is, $40 divided by 5. However, for purposes of this section, only $5 per day may be excluded, or $25 on a weekly basis.

(c) Expenses in respect of which the allowance under section 120 is paid may not be deducted under any provision of the income tax laws except to the extent that (1) such expenses exceed the amount of the exclusion, and (2) the excess is otherwise allowable as a deduction. For example, if a State statute provides a subsistence allowance of $3 per day and the taxpayer, a state trooper, incurs expenditures of $4.50 for meals while away from home overnight on official police duties only $3 would be excludable under this section. Expenses relating to such exclusion ($3) may not be deducted under any provision of the income tax laws. However, the remaining $1.50 may be an allowable deduction under section 162 as traveling expenses while away from home in the performance of official duties. See §1.162-2.

(d) In the case of taxable years ending after September 30, 1958, section 120 and this section do not apply to amounts received as a statutory subsistence allowance for any day after September 30, 1958.