You wrote that the lender will give you a 1099-MISC if you defaults on the loan. In computing taxable the taxpayer should only pay income tax on income or assets received. If you did not pay anything for the stock the 1099-MISC should be interest, plus value of the stock pledged, minus the value of the stock at time of default but, you wrote you paid $10 for the stock.
A canceled of debt is not reportable on Form 1099-MISC. Canceled debts are required to reported on Form 1099-C, Cancellation of Debt, by financial institutions.
Example: You take a loan from a lender in the amount of $100 and you used the $100 to buy stock. You default on the loan and the lender must report the amount to the IRS, issues you a 1099-C in the amount of $100. The stock is worthless. On you income tax return you will report the $100 as ordinary income and you will report the $100 as a capital loss (long-term if held over one year.).
If you are not using the proceeds of the loan to purchases the stock then I agree on the long-term capital gains.
You can always add a bonus to the $30.
Enrolled Agent
10 years self employed , Income Tax Preparation & Representation