On line 31 of the Schedule C is the loss. Right below are boxes 32a and b which indicates if all or some of the investment is at risk.
- If you checked 32a (All investment is at risk), enter the loss on both Form 1040, line 12, and on Schedule SE, line 2. (If you checked the box on line 1, see the line 31 instructions). Estates and trusts, enter on Form 1041, line 3.
- If you checked 32b (Some investment is not at risk), you must attach Form 6198. Your loss may be limited.
The Schedule C from 2017:
https://www.irs.gov/pub/irs-prior/f1040sc--2017.pdf
