We investigate bidder’s short- and long-term performance in periods of high and low valuation market in response to announcements of acquisitions carried out by Spanish listed firms over the period 1991–2016. We find that acquirers of unlisted targets fully react at the announcement date in high valuation periods, meanwhile the underreaction of listed target bidders at the moment of the announcement in low valuation markets is the result of return continuations. In addition, we find that the market reaction do not depend on recent merger history. Therefore, we provide evidence that bidder reaction to acquisitions is not consistent with the predictions of market sentiment (optimism) after controlling for the listing status of the target firm, not supporting, for a thinner market as the Spanish one, the evidence observed in US and UK markets. JEL CLASSIFICATION G14; G34; L33; D81