Suppose that in 2017 I bought 100 shares of XYZ stock. Would selling all these shares in 2018 for $900 worth of proceeds at a cost basis of $1,000 (realizing a capital loss of $100) increase my 2018 gross income by $900? Does the answer change depending on whether the capital loss is a short-term or long-term capital loss?
Note: I'm asking about gross income, not adjusted gross income (AGI), because I want to know if my gross income is less than my filing threshold.