The Supreme Court’s 2013 Amgen decision addressed whether a “merits” issue – the materiality of the alleged misstatement or omission – is such a predicate to the fraud-on-the-market presumption established in Basic Inc. v. Levinson that it must be proved (or at least subject to rebuttal) as part of class certification. The Court said no by a 6-3 majority, surprising many. This paper is a reader’s guide to Amgen and the future of the presumption of reliance. It explains the surprise (the pro-plaintiff outcome in contrast to the general trend in the class action case law) as a consequence of the view that Congress spoke to the relative balance between plaintiffs and defendants in the Private Securities Litigation Reform Act, thereby “freezing” the scope of the law as of that moment. While that has been a defendant-oriented argument to counter judicial expansiveness, in Amgen it becomes a two-way street, preserving as well as restraining. The paper also examines the skirmishing over the assumptions (and proof) of market efficiency and its relationship to materiality, reliance, causation and damages. Even though there are ample muddles in the law, none is so troubling as to call Basic into question, as Justice Alito’s concurrence suggests, especially if one believes in the relevance of not only what Congress did but also did not do in 1995. The paper draws from private correspondence between Justices Blackmun and Brennan when the Basic opinion was being drafted that sheds interesting light on the presumption and its contemporary meaning.