Worthless stock
In some cases, stock you own may have become completely worthless. If so, you can claim a loss equal to your basis in the stock, which is generally what you paid for it. The stock is treated as though it had been sold on the last day of the tax year. This date is important because it determines whether your capital loss is long-term or short-term.
Stock shares become worthless when they have no liquidation value, because the corporation’s liabilities exceed its assets, and no potential value, because the business has no reasonable hope of becoming profitable. A stock can be worthless even if the corporation hasn’t declared bankruptcy. Conversely, stock may still have value even after a bankruptcy filing, if the corporation continues operating and the stock continues trading.
You may not discover that a stock has become worthless until after you’ve filed your tax return for the year of worthlessness. In that case, you can amend your return for that year to claim a credit or refund due to the loss. This can be done for seven years from the date your original return was due, or two years from the date you paid the tax, whichever is later.