Business & farm

If you are a trader, and you have not made the Mark to Market election, you report your trades on Schedule D as you have indicated.   But dividends and interest and other expenses of your business are reported on Schedule C.   You are in the business of trading securities, so all business-related expenses and income are reported on your Schedule C.   When you elect Mark to Market, you use Form 4797, Sale of Business Property and your gains become business income which counts toward SE income for the purposes of making SE retirement account contributions. 

To create a Schedule C, use this link.  

Your trading activity is still reported on Schedule D, so your SE retirement contributions and health insurance premiums deductions are dependent upon your SE income, which for a trader without a Mark to Market election is limited to dividend and interest income.   If you had an S-corp, you could pay yourself a salary and use that earned income to contribute to a SE retirement plan.    But with your gain income reported on Schedule D, the income cannot be considered self-employment income.     @spencer00