After a product has been on promotion, the sales of that product may temporarily decrease. This post-promotion dip is normally explained in terms of forward buying or stockpiling. This article offers a third explanation in terms of brand switching. The results of two experiments show that after missing a discount on their regular brand, consumers may switch to another brand. Switching behavior is much more pronounced when a large discount is missed in comparison to when a small discount is missed. This finding is consistent with recent social psychological research on inaction inertia, and the results are discussed in relation to this phenomenon. © 2005 Wiley Periodicals, Inc.