Previous research on reputation systems primarily focused on their trust-building function. The present research addresses their trust-rebuilding function-specifically, the role of the short text comments given in reaction to negative feedback. Rebuilding trust is often necessary because on-line markets are noisy environments. The results of two experimental studies of eBay users show that trustworthiness judgments are influenced by the text comments accompanying negative feedback and also by whether a trust violation is perceived as competence-based or morality-based. Plain apologies were more successful than denials in repairing trust. These effects were mediated by the perceived believability of the comments. Thus, to avoid the detrimental effect of noise on trust, operators of on-line marketplaces should encourage text feedback comments and reactions. © 2009 M.E. Sharpe, Inc. All rights reserved.