Pershing acquired about 10 percent of Allergan and tried to push the Botox maker into a deal. Pyott, whose company was ultimately sold to Ireland-based Actavis for $66 billion, testified that he hoped the Securities and Exchange Commission will investigate the Ackman-Valeant pursuit, looking into "this novel structure with possible breach of insider trading laws and other securities regulations." Read More What to expect from the Actavis-Allergan merger Pyott said the U.S. tax code needs to be changed because it puts U.S. companies at a disadvantage.