Mass. Gen. Laws ch. 158 § 45
The members or stockholders in any corporation shall be jointly and severally liable for its debts or contracts in the following cases, and not otherwise:
First, For such as may be contracted before the original capital is fully paid in; but only those stockholders who have not paid in full the par value of their shares, and those who have purchased such shares with knowledge of the fact, shall be liable for such debts.
Second, For the payment of all debts existing at the time when the capital is reduced, to the extent of the amounts withdrawn and paid to stockholders.
Third, If special stock is created under section twenty-five, the general stockholders shall be liable for all debts and contracts until the special stock shall have been fully redeemed.
Fourth, For all money due to operatives for services rendered within six months before demand made upon the corporation, and its neglect or refusal to make payment.
Any such member or stockholder who pays, on a judgment or otherwise, more than his proportion of any such debt shall have a claim for contribution against the other members or stockholders.
Mass. Gen. Laws ch. 158, § 45