(a) If the taxpayer cannot use the entire amount of the research and development tax credit for the first taxable year in which the taxpayer applied for a research and development tax credit, then the excess may be carried over to succeeding taxable years and used as a credit against the qualified tax liability of the taxpayer for those taxable years. Each time that the research and development tax credit is carried over to a succeeding taxable year, it is to be reduced by the amount that was used as a credit during the immediately preceding taxable year. The research and development tax credit provided by this article may be carried over and applied to succeeding taxable years for no more than fifteen taxable years following the first taxable year for which the taxpayer was entitled to claim the credit.

(b) A research and development tax credit approved by the department for Pennsylvania qualified research and development expense in a taxable year first shall be applied against the taxpayer's qualified tax liability for the current taxable year as of the date on which the taxpayer applied for the credit before the research and development tax credit is applied against any tax liability under subsection (a).

(c) A taxpayer is not entitled to carry back or obtain a refund of an unused research and development tax credit.

(d) A taxpayer, upon application to and approval by the Department of Community and Economic Development, may sell or assign, in whole or in part, a research and development tax credit granted to the taxpayer under this article. The Department of Community and Economic Development shall establish guidelines for the approval of applications under this subsection.

(e) The purchaser or assignee of a portion of a research and development tax credit under subsection (d) shall immediately claim the credit in the taxable year in which the purchase or assignment is made. The amount of the research and development credit that a purchaser or assignee may use against any one qualified tax liability may not exceed seventy-five per cent of such qualified tax liability for the taxable year. The purchaser or assignee may not carry over, carry back, obtain a refund of or assign the research and development tax credit. The purchaser or assignee shall notify the department of the seller or assignor of the research and development tax credit in compliance with procedures specified by the department.