Stock investors who think their portfolios escaped the wave of lawsuits stemming from the opioid crisis should look again. While privately-owned Purdue Pharma has suffered nearly all the bad press and financial damage thus far, five major public companies could still face tens of billions in liabilities that threaten to wipe out big chunks of their market value. “Momentum has picked up significantly,” said Abbe Gluck, a professor of law at Yale University.