The Ninth Circuit concluded in a case of first impression that an employer could be held liable for its predecessor’s withdrawal liability to a multiemployer pension fund pursuant to the “successorship doctrine.”  The Court ruled that “the most important factor in assessing whether an employer is a successor for purposes of imposing MPPAA withdrawal liability is whether there is substantial continuity in the business operations between the predecessor and the successor, as determined in large part by whether the new employer has taken over the economically critical bulk of the prior employer’s customer base.”  The Ninth Circuit concluded that the district court failed to weigh whether the alleged successor had retained a significant portion of its predecessor’s customer base, or “market share.” In addition,