We investigate whether earnings guidance affects aggregate stock returns through its effects on expectations about overall earnings performance and/or aggregate expected returns. We find that aggregate guidance, especially relative levels of quarterly downward guidance, is associated with analyst- and time-series- based measures of aggregate earnings news. We find more modest evidence that guidance, again, largely downward guidance, is associated with market returns-market returns appear to respond to guidance toward the end of each calendar quarter, when most earnings preannouncements are released, and there is some evidence that firm-level guidance affects market returns in short windows around its release. (c) 2006 Elsevier B.V. All rights reserved.