The rabbit hole is getting deeper in the government's investigation of SAC Capital Advisors for alleged insider trading. The latest turn? The hedge fund's founder, Steven Cohen, has declined to testify to a grand jury, sending word to the government through his lawyers that he would invoke his right against self-incrimination. Although neither the firm nor Cohen have yet been charged with anything, it seems that his executives aren't taking any chances: five of those subpoenaed have met with lawyers in recent weeks for interviews. It's currently unclear whether those interviews will take the place of grand-jury testimony.