交叉購買被視為關係深化的表徵，且受關係品質良否的影響。但關係品質影響關係深化的程度與影響路徑為何？過去文獻著墨有限，值得探討。本研究除了試圖探究關係品質與交叉購買的關聯外，並考慮商品類別相似度與複雜度的雙重干擾：相似度為推進力量、複雜度則為節制力量，以建構一權變模式。本研究以金融業為例，將商品種類依相似度及複雜度高低分成四種交叉購買組合，以506位銀行端顧客為樣本，深究其向銀行交叉購買銀行傳統商品到保險與投資理財等之影響因素。結果顯示，關係品質中的滿意度與信任在四種交叉購買組合中的影響力互為消長：滿意度在高相似、低複雜度的商品組合中影響力最大，但隨相似度降低、複雜度增加，滿意度逐步喪失影響力，而信任則逐漸扮演重要角色終至獨挑大樑。

Prior studies examining the effects of trust and satisfaction on cross-buying have drawn mixed results. We expect that category similarity and complexity affect clients' cross-buying evaluation process. To gain a better understanding the relationship between satisfaction trust and cross-buying, we examine whether the effects of satisfaction and trust on crossbuying are moderated by category similarity and complexity separately. Second, we further examine that the effects of joint moderating effects of category similarity and complexity on the relationship of satisfaction, trust and cross-buying. In this study, the varying levels of category similarity and complexity development were conducted in a focus group consisting of three managers from a bank, an insurance company and a securities firm. Twenty financial products were divided by varying levels of category similarity and complexity. 103 EMBA students were pretested to judge category similarity and complexity. The manipulation check showed that there is a significant difference between low and high complexity categories and between low and high similar categories. Our sample included individual clients with a saving account with a bank in Taiwan. The final sample size was 506. We used hierarchical regression analysis to test our hypotheses. The moderating effects in the hypotheses were assessed by subgroup analysis. The procedure adopted was to divide the total sample into two groups on the basis of high/low category similarity and complexity. The results support that, along with the decreasing of category similarity and the increasing of category complexity, satisfaction gradually gives its way to trust in affecting customer's cross-buying insurance and investment services from banks. In other words, satisfaction has an effect on similar and simple cross-buying but does not have an effect on dissimilar and complex cross-buying. However, satisfaction and trust have equal effects on cross-buying under the joint conditions of high category similarity/high category complexity and low category similarity/low category complexity. Moreover, our results show that trust, rather than satisfaction, is a relatively more important antecedent of both dissimilar and complex cross-buying.