The IRS has specific regulations about how to write off worthless securities.  See Code of Federal Regulations – Title 26: Internal Revenue: 26 CFR 1.165-5 – Worthless securities.

A loss must be “realized” to be “recognized” and recognized when it is realized. The loss deduction for worthless securities must be taken for the tax year in which the  securities became worthless. How do you prove it is worthless and became worthless in the current taxable year?  Selling your “worthless asset” to CapGain Solutions provides documentation that your loss is realized in the year you sell to us.