If its public stock then yes. If it is a c corp then it may qualify for small business stock and a loss may be deducted. In order to qualify there are a few steps - (1) the corporation is a "qualified small business" upon issuance of the stock; and (2) the stock is acquired by the taxpayer at its original issue in exchange for money, other property (not including stock), or as compensation for services provided to the corporation.
A "qualified small business" is a domestic C corporation, the gross assets of which at all times on or after August 10, 1993 through the issuance of the stock in question do not exceed $50 million (without regard to liabilities). The corporation must be an "active business," rather than simply an investment company. A corporation will fail this requirement if more than 10% of the value of its net assets consists of stock and securities of other corporations (not including that of a subsidiary). In addition, a corporation does not meet this requirement if more than 10% of the total value of its assets consists of real property that is not used in the active conduct of a qualified trade or business. For these purposes, the ownership of, dealing in, or rental of real property is not considered the active conduct of a qualified trade or business.

For detremining the holding period (for short-term-held one year or less) (or long-term-held more than 1 year) is condidered worthless on the last day of the tax year.