Brandon L. Garrett, a professor at the University of Virginia School of Law and author of the forthcoming book, “Too Big to Jail: How Prosecutors Target Corporations,” said that while environmental and antitrust inquiries frequently resulted in corporate indictments, financial fraud investigators were just now “starting to see the light.” “Prosecutors have increasingly been saying that no company is too big to jail, and now they can point to the SAC case and say ‘We really mean it,’ ” Mr. Garrett said.