The loss on the sale of a personal residence is a nondeductible personal loss.

References:

• Publication 523, Selling Your Home
• Tax Topic 409, Capital gains and losses

If you own securities, including stocks, and they become totally worthless, you can take a deduction for a loss, but not for a bad debt.

The worthless securities are treated as though they were capital assets sold on the last day of the tax year. Report worthless securities on Form 1040, Schedule D (PDF), in Part 1 or 2 depending on whether you held the stock short term or long term, and write "Worthless" in the applicable column of Form 1040, Schedule D (PDF), Capital Gains and Losses. For additional information, refer to Chapter 4 of Publication 550, Investment Income and Expenses (Including Capital Gains and Losses) and Publication 552, Recordkeeping for Individuals. For more information on bad debts, refer to Tax Topic 453, Bad Debt Deduction.

The loss on the sale of rental property is reported on Form 4797 (PDF), (Sale of Business Property) as ordinary loss.

References:

• Form 4797 (PDF), Sale of Business Property
• Publication 544, Sales and Other Dispositions of Assets