Although still disputed by some authors, complement anaphora interpretations are widely accepted today. However, they are marked and subject to strict interpretation conditions. Most commonly, monotone decreasing quantifiers facilitate a salient complement set interpretation that is suitable for subsequent anaphoric reference, whereas monotone increasing quantifiers appear to block such interpretation. In this paper, I investigate the possibilities of anaphoric reference to complement sets in Spanish quantified expressions of type QUANTIFIER(A)(B) and argue that Spanish aligns with the general pattern observed cross-linguistically according to which anaphoric reference to the reference set (refset) is default regardless of monotonicity type, and that anaphoric reference to the complement set (compset) is only possible with monotone decreasing quantifiers. My claim is that the observed discrepancy can be explained in terms of the different proportions denoted by the quantifiers, and propose an explanation based on discourse relations. My approach provides additional cross-linguistic evidence in favor of the general observed pattern, and a promising path for future investigation into the refset/compset divide.