Section 31C. A manufacturing corporation, or a business corporation engaged primarily in research and development, which has been deemed to be such under section thirty-eight C or forty-two B, shall be allowed a credit as hereinafter provided against its excise due under this chapter. The amount of such credit shall be the amount determined by multiplying five hundred dollars by the increase in the number of full-time employees employed by the corporation during the taxable year, as hereinafter provided.

When used in this section the following terms shall have the following meanings:—

''Full-time employee'', an employee as defined in sections one and three of chapter one hundred and fifty-one A and who has been paid by the corporation during its taxable year an amount at least equal to the maximum amount of ''wages'' with respect to which an employer is required to make contributions pursuant to section fourteen of said chapter and said amount is includable in the payroll factor of the income apportionment formula under the provisions of section thirty-eight.

''Increase in the number of full-time employees employed by the corporation'', (i) in the case of a corporation having full-time employees in its taxable year ending last prior to December thirty-first, nineteen hundred and seventy-three, the excess of the number of full-time employees employed by the corporation during its taxable year over the number determined by multiplying the number of full-time employees employed by the corporation during its taxable year ending last prior to December thirty-first, nineteen hundred and seventy-three, by the applicable coefficient for the taxable year, as herein set forth.

The coefficient shall be one and three hundredths for taxable years ended on or after December thirty-first, nineteen hundred and seventy-three, and before December thirty-first, nineteen hundred and seventy-four; one and six hundredths for taxable years ended on or after December thirty-first, nineteen hundred and seventy-four, and before December thirty-first, nineteen hundred and seventy-five; one and nine hundredths for taxable years ended on or after December thirty-first, nineteen hundred and seventy-five, and before December thirty-first, nineteen hundred and seventy-six; one and twelve hundredths for taxable years ended on or after December thirty-first, nineteen hundred and seventy-six, and before December thirty-first, nineteen hundred and seventy-seven; and one and fifteen hundredths for taxable years ended on or after December thirty-first, nineteen hundred and seventy-seven, and before December thirty-first, nineteen hundred and seventy-eight;

(ii) in the case of a corporation not having a taxable year ending prior to December thirty-first, nineteen hundred and seventy-three, by reason of recent organization or registration or by reason of not being subject to taxation in the commonwealth or not having any full-time employees in its taxable year ending last prior to December thirty-first, nineteen hundred and seventy-three, the excess of the number of full-time employees employed by the corporation during its taxable year over the number determined by multiplying the number of full-time employees employed by the corporation in the first taxable year in which the corporation may take the credit provided for in this section by the applicable coefficient for the taxable year as herein set forth. The coefficient shall be zero for the first taxable year. The coefficient shall be twenty hundredths for the second taxable year. The coefficient shall be forty hundredths for the third taxable year. The coefficient shall be sixty hundredths for the fourth taxable year. The coefficient shall be eighty hundredths for the fifth taxable year.

(a) A corporation which is a successor to another employing unit, as defined in section one of chapter one hundred and fifty-one A, by reason of an acquisition or other activity referred to in subsections (d) to (h), inclusive, of section eight of said chapter one hundred and fifty-one A shall, for purposes of this section, treat the employees of such employing unit as having been employees of the corporation during the periods they were employees of such employing unit. For the purposes of this section the activities referred to in said subsections (d) to (h), inclusive, of said section eight of said chapter one hundred and fifty-one A shall include but not be limited to applicable provisions of sections three hundred and one to three hundred and ninety-five, inclusive, of the Internal Revenue Code, as amended, and in effect for the taxable year relating to corporate distributions and adjustments. For the purpose of this section, a corporation having a taxable year ending prior to December thirty-first, nineteen hundred and seventy-three, shall be treated as if it had such a taxable year if, under this paragraph, the corporation is treated as having employees prior to such date.

(b) For a corporation having a taxable year of less than twelve months, herein referred to as a short period, an employee shall be deemed to be a full-time employee if the amount of the remuneration paid to him by the corporation during the short period when multiplied by twelve and divided by the number of months in the short period is at least equal to the maximum amount of wages with respect to which an employer is required to make contributions pursuant to section fourteen of chapter one hundred and fifty-one A. The credit for a short period shall be computed in the same manner as for a full taxable year but shall be reduced by multiplying the credit so determined by the number of months in the short period and dividing the result by twelve.

(c) A corporation shall not be allowed a credit under this section with respect to any increase in the number of full-time employees employed by the corporation during its taxable year and first employed by such corporation during a taxable year ending on or after December thirty-one, nineteen hundred and seventy-three, in excess of the sum of the following:—

(1) the number of full-time employees employed by such corporation during such taxable year who immediately prior to employment by such corporation:—

(i) were receiving assistance under the provisions of chapters one hundred and fifteen, one hundred and seventeen or one hundred and eighteen; provided that certification of the receipt of such assistance shall be obtained from the secretary of health and human services and shall be in such form as the commissioner shall prescribe;

(ii) had filed for and were receiving a money allowance under the provisions of chapter one hundred and fifty-one A, provided that eligibility to receive such money allowance shall be based solely on wages paid by an employer or employers other than such corporation or employing unit; and, provided further that certification of such eligibility and such receipt shall be obtained from the secretary of manpower affairs and shall be in such form as the commissioner shall prescribe;

(iii) were receiving training in a publicly or privately funded training or rehabilitation program, including courses of instruction in recognized public or private educational institutions, approved by the director of career services or the secretary of health and human services, whichever is appropriate, as one established to upgrade the job skills, wages and employment or promotional possibilities of persons who have already entered the work force, not including students regularly enrolled in such courses of instruction in such institutions; provided that certification of the approval of such program and the receipt of such training shall be obtained from such secretary and shall be in such form as the commissioner shall prescribe;

(iv) were receiving training under an approved training or assistance program as defined in paragraph (b) of section eleven of chapter twenty-three B; provided that certification of the approval of such program and the receipt of such training shall be obtained from the director of housing and community development and shall be in such form as the commissioner shall prescribe;

(v) were receiving training or had received training in any program operated by the department of corrections for persons committed to its custody under the provisions of section forty-eight of chapter one hundred and twenty-seven which will upgrade the job skills and employment possibilities of the participants in such program; provided that certification of the receipt of such training shall be obtained from the secretary of human services and shall be in such form as the commissioner shall prescribe;

(2) the number of full-time employees employed by such corporation during such taxable year who immediately prior to employment by such corporation were not receiving or had not received such assistance, allowance or training, but who subsequent to such employment completed or at the close of such taxable year were participating in a training or rehabilitation program which is conducted or subsidized by such employer and established in accordance with guidelines prescribed by the director of career services and certified by said director as one which had the prior approval of said director and as one which will upgrade the job skills, wages, and promotional possibilities of the participants in such programs; provided that such certification shall be in such form as the commissioner shall prescribe.

In order to verify the certification required by clauses (i) to (v), inclusive, or otherwise determine the eligibility of an employee under this subsection the commissioner is authorized to receive information with respect thereto from the appropriate secretary or department notwithstanding any other provision of law which may prohibit the disclosure of such information.

(d) The credit allowed under this section shall be in addition to the credit allowed under section thirty-one A; provided, however, that the sum of the credit allowed under said section thirty-one A and the credit allowed under this section shall not reduce the excise to less than the amount due under subsection (b) of section thirty-two, subsection (b) of section thirty-nine or section sixty-seven and under any act in addition thereto.

A corporation may elect to deduct the amount allowable under section thirty-eight F or the credit under this section, but not both. Any such election must be made annually on or before the due date of filing the return, including any extension of time and shall be irrevocable.

The credit allowed by all provisions of this section except subdivision (2) of subsection (c) shall be for taxable years ending on and after December thirty-first, nineteen hundred and seventy-three, and prior to December thirty-first, nineteen hundred and seventy-eight, and the credit allowed under the provisions of said subdivision (2) of said subsection (c) shall be for taxable years ending on and after December thirty-first, nineteen hundred and seventy-four, and prior to December thirty-first, nineteen hundred and seventy-eight; provided that any corporation claiming such credit shall furnish such information relative to the credit as may be required by the commissioner in a form approved by the commissioner.