Section 1-503 - Joint and several liability; contribution; corporation's right of indemnification(a) Every affiliate of a person liable under section 501 or 502, every partner, principal executive officer or director of such person, every person occupying a similar status or performing similar functions, every employe of such person who materially aids in the act or transaction constituting the violation, and every broker-dealer or agent who materially aids in the act or transaction constituting the violation, are also liable jointly and severally with and to the same extent as such person, unless the person liable hereunder proves that he did not know, and in the exercise of reasonable care could not have known, of the existence of the facts by reason of which the liability is alleged to exist.(b) A corporation which is liable under this act shall have a right of indemnification against any of its affiliates whose wilful violation of any provision of this act gave rise to such liability. All persons civilly liable under this act shall have a right of contribution against all other persons similarly liable, based upon each person's proportionate share of the total liability, except that no person whose wilful violation of any provision of this act has given rise to any civil liability shall have any right of contribution against any other person guilty merely of a negligent violation.1972, Dec. 5, P.L. 1280, No. 284, § 503, effective 1/1/1973.