Pennsylvania Statutes Title 40 P.S. Insurance § 781. Employers' mutual liability insurance associations defined

An incorporated association or company heretofore or hereafter formed by employers for the purpose of insuring themselves, and such other employers as may become subscribers to the association, against liability under the terms of articles two and three of “The Workmen's Compensation Act of one thousand nine hundred and fifteen,” or any amendments or supplements or revisions thereof,  1 shall be known as an “employers' mutual liability insurance association.”