If any credit remains after application of the credit against tax for any taxable year under this article, the amount thereof shall be carried forward to each ensuing tax year until used or until the first day of July, two thousand ten, whichever occurs first. If any unused credit remains after the first day of July, two thousand ten, the amount thereof is forfeited. No carryback to a prior taxable year is allowed for the amount of any unused portion of this credit.
W. Va. Code § 11-13T-5