26 U.S.C. § 174
Section 174 · Research and experimental expenditures
Current version, with additions and removals from the December 22, 2017 version.
This section shall not apply to any expenditure for the acquisition or improvement of land, or for the acquisition or improvement of property to be used in connection with the research or experimentation and of a character which is subject to the allowance under section 167 (relating to allowance for depreciation, etc.) or section 611 (relating to allowance for depletion); but for purposes of this section allowances under section 167, and allowances under section 611, shall be considered as expenditures.
This section shall not apply to any expenditure paid or incurred for the purpose of ascertaining the existence, location, extent, or quality of any deposit of ore or other mineral (including oil and gas).
For purposes of this section, any amount paid or incurred in connection with the development of any software shall be treated as a research or experimental expenditure.
This section shall not apply to any expenditure for the acquisition or improvement of land, or for the acquisition or improvement of property to be used in connection with the research or experimentation and of a character which is subject to the allowance under section 167 (relating to allowance for depreciation, etc.) or section 611 (relating to allowance for depletion); but for purposes of this section allowances under section 167, and allowances under section 611, shall be considered as expenditures.
This section shall not apply to any expenditure paid or incurred for the purpose of ascertaining the existence, location, extent, or quality of any deposit of ore or other mineral (including oil and gas).
For purposes of this section, any amount paid or incurred in connection with the development of any software shall be treated as a research or experimental expenditure.